Strongly Dem (41)
Likely Dem (3)
Barely Dem (2)
Exactly tied (0)
Barely GOP (2)
Likely GOP (1)
Strongly GOP (51)
No Senate race

New polls:

Dem pickups :

GOP pickups :

Here is a compact table listing all of the Senate candidates known at this point. Some haven't been chosen yet and will not be until the primary in late June or August.

The current breakdown of the Senate is as follows (where we count the two independents as Democrats):

10 Democratic seats up for reelection in 2016 and 36 seats not up, for a total of 46 seats
24 Republican seats up for reelection in 2016 and 30 seats not up, for a total of 54 seats

In a reversal from 2014, the Democrats will be playing offense, trying to pick up at least five seats (or four seats and the vice-presidency) in order to reclaim control of the Senate. As they do so, there are several pieces of good news for them:

The party has had enormous success this year in recruiting top candidates, not only in states where the Democrats' chances are excellent, but also in states where their chances are only middling. By contrast, outside of Nevada, the Republicans have struck out with their preferred candidates.
There is only one Democratic-held seat that is presently in play (Nevada), and one other that could conceivably join the list (Colorado). In contrast, as many as 16 Republican-held seats are or could be in play, with at least six of those being in significant danger (Wisconsin, Illinois, Pennsylvania, Florida, Ohio, and New Hampshire, in roughly that order).
The Republicans are defending so many seats, and in so many expensive states, that they will almost certainly be compelled to do some triage after primary season and to declare some races to be lost causes.
Presidential election years generally favor the Democrats, as they bring more voters to the polls, especially minorities, young people, and single women.
Hillary Clinton, if she is indeed the Democratic nominee, may prove to have unusually large coattails. As a woman, she could attract female voters to the polls. As a former First Lady of Arkansas, she could impact Florida or Missouri or Arkansas in a way that John Kerry and Barack Obama could not.

The news is not all bad for the Republicans, however:

The 2016 election is not a total mirror image of 2014. In that election, the Democrats' "in play" seats were in very red states like Alaska and Montana. This year, the Republicans' "in play" seats are largely in purple or light blue states like Ohio, New Hampshire, Florida, and North Carolina. In other words, the Republicans have an easier position to defend in 2016 than the Democrats did in 2014.
The tea party's influence appears to be waning, in part due to changes in the economic climate, and in part due to a series of embarrassing electoral defeats. Compared to 2012 and 2014, it is much less likely (albeit not impossible) that the Republicans will blow a competitive race by nominating someone like Christine O'Donnell, Todd Akin, or Sharron Angle.
North Dakota's Class 1 Senate Seat, held by Democrat Heidi Heitkamp, is not among the seats up for election this year and so is not technically in play. However, it could become so, should Heitkamp run for governor and win. See below for more.
Even if they lose control of the Senate next year, the 2018 map will once again favor the Republicans, as the Democrats will be defending 23 seats in a nonpresidential year, including those in the red (or reddish) states of Indiana, Missouri, Montana, North Dakota and West Virginia. Should they wish to secure control of the Senate until the next presidential election, the Democrats will likely need a net gain of eight or nine seats this year—a very tall order.

The Democratic-held seats are listed first below, in alphabetical order by state, with the Republican ones following.

Click on a picture for the candidate's webpage.
Click on a name for the candidate's entry in Wikipedia.
Click on a party (D) or (R) for the state party.

The indicates a race to watch.

All links open in a new window. Type CTRL-W in the window to close it (Command-W on a Mac).

Democratic-held seats

California

Challenger	Challenger	Notes Polls
Kamala Harris (D)	Loretta Sanchez (D)	Barbara Boxer is retiring, and it's a two-woman race to be the Democrat that succeeds her. California Attorney General Kamala Harris is the first person of African or Asian descent to occupy that office (her father is Jamaican and her mother is Indian). She thus has ties to two constituencies that play an important role in California politics (7% of the population and 13%, respectively). Harris is also well connected to power brokers within the Democratic Party, who see her as a rising star and a possible presidential candidate in 2020 or 2024. She will undoubtedly get Boxer's endorsement, as both women hail from Northern California and from the liberal wing of the party. The alternative is nine-term representative Loretta Sanchez, who presents a fairly striking contrast to Harris. Coming from a conservative district in Southern California, Sanchez is a leading Blue Dog (conservative) Democrat with strong ties to the Latino community. Another pair of Democrats and a half-dozen Republicans have declared their candidacies for this seat, with Ron Unz—best known for helping launch the recall that put Arnold Schwarzenegger in the governor's mansion—the latest entrant. They are not factors, however, and indeed, the most prominent Republican contender, Assemblyman Rocky Chávez, quit the race right in the middle of the first senatorial debate. The lack of a serious Republican challenger plus California's jungle primary system mean that Sanchez and Harris will likely face one another in June and then again in November, despite being from the same party. Harris has burned through multiple campaign managers and quite a bit of money, but she's out-fundraising Sanchez by a wide margin ($10 million to $3 million) and she's leading by 5-15 points in early polls. One possible wild card: There are whispers that Harris might be tapped as the Democrats' VP candidate. Not likely, but if it happens, then Sanchez will definitely be California's next U.S. Senator.

Colorado

Incumbent	Challenger	Notes Polls
Michael Bennet (D)	Candidate Unknown (R)	Support for Michael Bennet is tepid in Colorado, and given that the state is purplish with a strong libertarian bent, Republicans see this as their second-best opportunity (behind Nevada) to take a Democratic-held seat in 2016. That assessment may be technically accurate, but "second-best chance" does not necessarily mean "good chance." To start, Bennet is the former head of the Democratic Senatorial Campaign Committee (DSCC) and a prodigious fundraiser—he has raised more money this cycle ($9.5 million) than all but three of his Senate colleagues. Further, the Republican side of the contest has been a bloodbath, with no less than 14 candidates scrapping with one another for the nomination. That number has now been narrowed to four; the favorite among them is El Paso County Commissioner Darryl Glenn, a black Air Force veteran and staunch conservative who was voted onto the June 28 ballot by the Colorado state Republican convention (his three opponents, by contrast, got onto the ballot by collecting signatures). In any case, whoever emerges victorious on the GOP side will be bloodied and out of money (in fact, Glenn has raised only $45,000 so far). The "x-factor" on which some Colorado Republicans are hanging their hats is Donald Trump—Colorado has an unusually high number of independent voters, and their hope is that he will bring lots of Republicans and independents to the polls to vote for Bennet's challenger. It's an interesting fantasy, but that's about it, particularly given how badly Trump performed at the state convention.

Connecticut

Incumbent	Challenger	Notes Polls
Richard Blumenthal (D)	Candidate Unknown (R)	Richard Blumenthal kept his head down and his nose clean during his first six years in the Senate and now wants a second term, which he will get. A very blue state, Connecticut has no statewide officeholders who are Republican and has not sent a Republican to the U.S. Senate since the 1980s. Wrestling magnate Linda McMahon was the GOP candidate for the last two elections; this time, the party will be looking for another freebie (i.e., a candidate who can completely self fund and not cost the party anything). The most likely possibility is investment banker and former Olympian Augie Wolf, who has zero political experience but has decided it will be be fun to run. If he stays the course, he better be ready to take home the silver; the only poll conducted thus far has Blumenthal beating Wolf by 35 points. State Rep. Dan Carter has also recently declared, but while he has actual political experience, his chances won't be much better if he takes the GOP nomination.

Hawaii

Incumbent	Challenger	Notes Polls
Brian Schatz (D)	Candidate Unknown (R)	Hawaii is the bluest state in the Union. When Brian Schatz ran in the 2014 special election to succeed deceased Senator Daniel Inouye, he beat his Republican opponent by 40 points (President Obama did even better in 2012, winning the state by 46). Hawaii has not given its electoral votes to the GOP since the Reagan landslide of 1984, and has only ever elected one Republican to the U.S. Senate (Hiram Fong, who served from 1959 to 1976). The only possible threat to Schatz, then, would have to come in the primaries. Former Representative Colleen Hanabusa was Inouye's preferred successor, lost the 2014 primary to Schatz by less than 2,000 votes (out of 230,000), and is considering a second run. She has until June 7 to decide. If she jumps in, Schatz will sweat a little, but he would still be the clear favorite. Ethnic politics is important in Hawaii (Schatz is Jewish and Hanabusa is Japanese-American) but not definitive. Whatever happens, this will be a Democratic seat when the 115th Congress convenes in 2017.

Maryland

Challenger	Challenger	Notes Polls
Chris Van Hollen (D)	Kathy Szeliga (R)	Popular senator Barbara Mikulski is retiring after five terms. While Marylanders sometimes elect Republicans to statewide office (e.g., Gov. Larry Hogan in 2014), they turn deep blue when voting for senators. Mikulski won by 25 points in 2010, and her junior counterpart Benjamin Cardin won by 30 in 2012. The drama, then, was in the Democratic primary. Maryland has a deep bench of top-tier Democratic candidates, two of whom ultimately threw their hats into the ring. Emerging victorious after a brutal, racially-polarized contest was seven-term representative Chris Van Hollen, who managed to comfortably outpoll Rep. Donna Edwards. Born in Pakistan to an officer of the U.S. Foreign Service, he has won much praise for his expertise in foreign affairs and budgetary matters. In the general election, he will face Maryland House Minority Whip Kathy Szeliga, who he has out-fundraised by a margin of 20-to-1 and who he will easily crush.

Nevada

Challenger	Challenger	Notes Polls
Catherine Cortez-Masto (D)	Joe Heck (R)	Senate Minority Leader Harry Reid is retiring after five terms—perhaps because of age, perhaps because of a recent injury that left him blind in one eye, perhaps because he is tired of tough reelection campaigns. The most likely explanation, however, is that he beat nondescript, gaffe-prone tea partier Sharron Angle by only 6 points in 2010 and might well lose to a more serious candidate in 2016. Whatever the case may be, Reid will yield the Democratic mantle to his handpicked successor, Catherine Cortez Masto, who served eight years as Attorney General of Nevada before being term limited. If elected, she would be the first Latina to serve in the U.S. Senate (though she could end up sharing that honor with Loretta Sanchez). Enjoying wide name recognition across the state, Masto will have the considerable financial and logistical resources of Reid's political network at her disposal. The Republican candidate will almost certainly be two-term representative Joe Heck, who surprised and delighted the party establishment when he decided to run. A physician and brigadier general in the U.S. Army Reserve, Heck is an excellent campaigner and fundraiser who gives the Republicans far and away their best chance to capture a Democratic-held Senate seat in 2016. He will consistently remind voters that he has Washington experience and Masto does not (although, given how unpopular "Washington" is, maybe Masto will be the one doing the reminding.) Heck will have to fend off a challenge from Angle, who has decided she will return for another bite at the apple. He should be able to do so, though it could damage him quite a bit. He's already been compelled to defend the GOP's approach to the Supreme Court, which could hurt him in the general election. This looks to be a very close race, and millions of dollars will pour in from outside of Nevada. In particular, the Koch brothers are targeting Nevada for some of the money that they presumably won't be spending on the presidential contest. The deciding factor could well be how many of the state's 780,000 Latinos go to the polling place on Election Day.

New York

Incumbent	Challenger	Notes Polls
Chuck Schumer (D)	Wendy Long (R)	New York is a very blue state and Chuck Schumer is popular, has $26 million in the bank (twice as much as any other 2016 Senate candidate), and knows how to make use of the advantages of incumbency. He is also an aggressive self-promoter. As Bob Dole once observed, "The most dangerous place in Washington is between Chuck Schumer and a camera." (This infinitely recyclable joke was originally told about Theodore Roosevelt more than a century ago). Schumer won his last election by 33 points, and the one before that by nearly 50. His opponent will be lawyer Wendy Long, a political novice whose main claim to fame is losing the 2012 Senate race to Kristen Gillibrand by 43 points. So, there's nothing to see here, unless you happen to like carnage; early polls have Schumer up by 40 points. Once he wins his fourth term, Schumer will likely take over for Harry Reid as leader of the Senate Democrats.

Oregon

Incumbent	Challenger	Notes Polls
Ron Wyden (D)	Candidate Unknown (R)	A cancer scare had Ron Wyden considering retirement, but he's healthy now and gunning for a fifth term. He is one of the most liberal members of the U.S. Senate, and that suits deep-blue Oregon just fine; voters have bestowed an average margin of victory of 30 points upon him in his three previous reelection campaigns. Meanwhile, there is no Republican bench in the state. The only member of the GOP currently representing Oregon at either the state or federal levels is Rep. Greg Walden, and he is content to keep his very safe seat in the House. Whatever candidate the party fields—four aspirants have declared—will be a political unknown, just like Wyden's last two opponents. Those four, two of them perennial candidates who run for whatever office presents itself, have raised a grand total of $200,000 between them thus far. That's less than 5% of the $7 million Wyden has brought in. This is going to be one of the Democrats' easiest holds.

Vermont

Incumbent	Challenger	Notes Polls
Patrick Leahy (D)	Candidate Unknown (R)	Patrick Leahy is, interestingly, the only Democrat ever elected to the U.S. Senate from the state of Vermont. That unexpected quirk is a byproduct of his extremely long term of service, coupled with the fact that his junior colleague Bernie Sanders is so far left that he identifies as a Democratic Socialist. When Leahy began his career in the 1970s, Vermont was reddish-purple, and he had to contend with difficult campaigns and close elections. However, he has not had to break a sweat since the last time a Clinton tried to move into the White House—1992—when he won by "only" 10 points. Vermont was in the process of turning very blue then, and Leahy has won every election since by at least 35 points. Now the Dean of the Senate, he will easily win an eighth term, possibly without opposition, putting him within striking distance of Robert Byrd's record nine terms and 51 years in the Senate. There is no Republican sacrificial lamb...er, challenger so far, and there may not be one. We will know for sure on May 26.

Washington

Incumbent	Challenger	Notes Polls
Patty Murray (D)	Candidate Unknown (R)	Patty Murray was nearly toppled by the Republican wave in 2010, winning her fourth term by less than 4 points. Her position is stronger now; she played a leading role in averting a government shutdown in 2013, and this cycle she has raised an impressive $6.7 million for her campaign. The only serious Republican to declare so far is former State Rep. Chris Vance, who is no real threat. Pollsters have largely ignored the race, and the one time they did take a look, Vance trailed Murray by 21 points. Even if the Republicans come up with someone better—they have about two weeks until the filing deadline—she is going to get her fifth term.

Republican-held seats

Alabama

Incumbent	Challenger	Notes Polls
Richard Shelby (R)	Ron Crumpton (D)	The last time Alabama sent a Democrat to the U.S. Senate was in 1994, when they elected...Richard Shelby. Then a Dixiecrat who was finishing his first term, he promptly changed parties after the election and became part of the "Contract with America" Republican wave. In the two decades since, Alabama has gone from being light red (+6 for Bush in 1992 and for Dole in 1996) to deep red (+22 for Romney), and Shelby has consistently won by a 2-to-1 margin when up for reelection. No Democrat stands a chance against him in 2016. Consequently, the best the Party could come up with is political novice and marijuana activist Ron Crumpton, who—appropriately enough—appears to be stoned in every picture he's ever posed for. This is not going to play well in socially-conservative Alabama, as indicated by the fact that Shelby has $9.6 million on hand, while Crumpton has raised the princely sum of $13,794. Crumpton's dream of going to the U.S. Senate will unquestionably go up in smoke on Election Day.

Alaska

Incumbent	Challenger	Notes Polls
Lisa Murkowski (R)	Candidate Unknown (D)	During her first full term in the Senate, Lisa Murkowski was a reliable "Main Street" (moderate) Republican. Her reward for this, when she ran for reelection in 2010, was to be primaried by tea partier Joe Miller. Murkowski countered by running as an independent, becoming only the second person to win a regular U.S. Senate election as a write-in candidate (the first was Strom Thurmond, and he did it with a name that is much easier to spell). In her second term, Murkowski has moved in a centrist direction, presumably an acknowledgment that the far right of the political spectrum is a lost cause for her. She is presently the most popular politician in Alaska (sorry, Sarah Palin!) and has more than $3 million on hand—a veritable fortune in Alaska, where men are men and advertising is cheap. But while it is good to be a fairly popular, well-heeled incumbent in a state dominated by your party, Murkowski has reason to worry. Her favorability ratings among Alaska Republicans are poor, and challengers are starting to circle, with retired U.S. Army colonel Margaret Stock already declaring a bid as an independent and perennial candidates Thomas Lamb and Bob Lochner doing the same as Republicans. Stock could be problematic for Murkowski—a Harvard-educated immigration attorney and former law professor, she is also recipient of a MacArthur Foundation "genius" grant. In addition to immigration, she is a specialist in national security issues, and she regularly consults for the U.S. army. Given her resume and her choice to run as an independent, she has the potential to cobble together a coalition of Republicans unhappy with their senator, libertarians, independents, and Democrats. Indeed, if the blue team is smart, they will choose not to field a candidate in exchange for a promise that Stock will caucus with them. There's been no polling yet, but it could get dicey for Murkowski.

Arizona

Incumbent	Challenger	Notes Polls
John McCain (R)	Ann Kirkpatrick (D)	As he tries for a sixth term, John McCain has the advantages of near-universal name recognition, $5.5 million in the bank with a prodigious ability to raise more, and status as a war hero for everyone except Donald Trump. In solidly red Arizona, his margin of victory in his five previous Senate contests has never been less than 24 points. However, that's where the good news ends, as the 2008 GOP presidential nominee is now facing the fight of his life. To start, he has drawn a formidable opponent in popular Democratic representative Ann Kirkpatrick, with early polls putting McCain up by only 6-7 points, and more recent polls calling it a dead heat. McCain is also dealing with a challenge from the right the form of tea partier Kelli Ward. He is trying to brush Ward aside, but she's hitting him hard, already running a commercial pointing out that McCain does not always oppose letting refugees into the United States. The state party has already censured McCain once for not being Republican enough, and it's not impossible that Ward could knock him off; at very least, she'll cost him some time and money. On top of that, the Senator has been hit by scandal, as one of his lead fundraisers (Emily Pitha) was arrested for running a meth lab. And if the triple play of Kirkpatrick, Ward, and Pitha were not enough, the circumstances of 2016 are also problematic for McCain. He won't be able to get rid of Ward for good until the primary on August 30, giving him only eight weeks to focus on the general election if he survives. And in the general, no state is more likely to be affected by Trump than Arizona, who figures to draw an inordinate number of the state's 2 million Latinos to the polls to vote a Democratic ticket. Finally, the cherry on top of McCain's sundae full of trouble is that he will be 80 on Election Day, has a lengthy history of nagging health problems, and has publicly acknowledged that he's running out of steam. The upshot it that a seat that has been safely Republican for decades (since 1968, to be precise) is now in toss-up territory, and if any giant of American politics is going to be toppled in 2016, Eric Cantor-style, it is going to be John McCain.

Arkansas

Incumbent	Challenger	Notes Polls
John Boozman (R)	Conner Eldridge (D)	John Boozman won his first Senate contest by 21 points, one of the many Republican successes in the 2010 midterm elections. As time passes, however, this victory is seeming more and more like it came despite Boozman, rather than because of him. He has proven to be a poor fundraiser and an unpopular senator, with a mediocre 34% approval rating. He has also had health problems, including emergency bypass surgery in 2014. These things being the case, he will be more vulnerable than most Southern Republicans. The Democratic establishment tried to recruit a strong opponent, such as former governor Mike Beebe, but ultimately ended up settling on federal prosecutor Conner Eldridge. Eldridge will have an uphill battle, as early polls have him trailing by a mile, but he's not a sitting duck. He can run a law and order campaign, and he may benefit from Hillary Clinton's coattails and from Bill Clinton campaigning in the state. Eldridge is also working to connect Boozman with Donald Trump, and has been airing a commercial full of Trump's misogynistic statements in an effort to curry favor with women voters. The bottom line: Bet on Boozman, if you must, but don't bet much.

Florida

Challenger	Challenger	Notes Polls
Candidate Unknown (R)	Candidate Unknown (D)	As we learned in 2000, Florida is a large state with many different constituencies, and is fairly evenly divided between Republicans and Democrats. These facts, coupled with the retirement of Sen. Marco Rubio so that he could run for president, leave the stage set for a battle royale that will be the most expensive Senate race in U.S. history. On the Democratic side, Reps. Patrick Murphy and Alan Grayson will square off. Murphy is a moderate (and a former Republican) and is viewed as more electable, so he has the backing of the DSCC and the establishment, including endorsements from Barack Obama Joe Biden. He's raised almost $8 million this cycle. Grayson is an outspoken liberal who tends to do impolitic things like compare the tea party to the Ku Klux Klan. One of the wealthiest members of Congress, he is able to compensate for a lack of establishment funds by taking out his checkbook. However, his campaign is in disarray, he's facing an ethics probe, and the establishment is leaning heavily on him to throw in the towel. So, the odds are it will be Murphy. On the Republican side, Lt. Gov. Carlos López-Cantera and Rep. David Jolly will both try to court the moderate vote. If they split it, it could allow Rep. Ron DeSantis, a tea party favorite, to claim the Republican nomination. Pollsters who have looked at the various permutations give the edge to the Democrats, though we likely won't have real clarity on this race until the primary is held on August 30.

Georgia

Incumbent	Challenger	Notes Polls
Johnny Isakson (R)	Candidate Unknown (D)	Johnny Isakson is very popular in Georgia, having won his first two Senate races by 18 and 19 points, respectively. He loves Jesus and hates taxes, gay marriage, abortion, and ObamaCare, so he's not vulnerable to a tea party challenge. In June of 2015, he revealed that he has been diagnosed with Parkinson's disease, but thus far the news has not affected his reelection plans. A trio of Democrats and a pair of Republicans have all thrown their hats into the ring, but they are all unknowns. This seat is not in play now, nor is it going to be on Election Day.

Idaho

Incumbent	Challenger	Notes Polls
Mike Crapo (R)	Jerry Sturgill (D)	Mike Crapo was bracing for a possible primary challenge from Rep. Raul Labrador, but Labrador decided to remain in the House. Meanwhile, the Democratic Party of Idaho is like the Loch Ness monster—rumored to exist, but actual evidence is scarce. They have not managed to get a senator elected since the 1970s, and that streak will continue in 2016. The only Democratic candidate to declare before the filing deadline was Jerry Sturgill, a lawyer and investment banker who is a political unknown. The only real question in this race, then, is whether Crapo will improve upon the 71% of the vote he received in 2010.

Illinois

Incumbent	Challenger	Notes Polls
Mark Kirk (R)	Tammy Duckworth (D)	Mark Kirk was a very moderate representative, and for the past six years he's been a very moderate senator. Unfortunately for him, "moderate Republican" was barely viable in the Republican wave of 2010 (Kirk won his seat by less than 2 points), and in presidential years Illinois turns very blue. The Senator's tendency to put his foot in his mouth is not helpful, either. In just the last year, he has had to apologize for characterizing bachelor Sen. Lindsey Graham (R-SC) as "a bro without hos," for describing black communities as "the one(s) we drive faster through," and for accusing President Obama of trying to "get nukes to Iran." If these liabilities were not enough, Kirk also suffered a serious stroke in early 2012, which was followed by a long and arduous recovery. He has been running a commercial, entitled "Courage," that tries to curry favor by linking his military service and his fight to overcome this disability. That commercial would be much more helpful if his opponent was not Tammy Duckworth, who lost both legs while serving as a helicopter pilot during the Iraq War. A charismatic two-term representative, Duckworth is the first disabled woman ever elected to the House, and the first Asian American to be elected to Congress from Illinois (she's Thai). That said, she too has some political baggage to contend with. She has no statewide experience, is presently the defendant in a lawsuit from her time as Director of the Illinois Department of Veterans Affairs, and she may not appeal to black voters (a critical Democratic constituency in Illinois). She passed her first test with flying colors, though, crushing Chicago Urban League President and CEO Andrea Zopp in the primaries. The first post-primary poll has Duckworth leading Kirk by 6 points, and that was before Donald Trump was the presumptive GOP nominee. Kirk has tried to have it both ways; giving cautious support to the billionaire in hopes of currying favor with his base, but also avoiding an actual endorsement. Duckworth has seized upon that and is already trying to paint Kirk and Trump as best buddies. It appears then, that despite her potential weaknesses, Duckworth is going to be elected Illinois' new junior senator. The Democratic Party will pull out all the stops to see that happens, as they are already counting this seat as a +1 in their column.

Indiana

Challenger	Challenger	Notes Polls
Todd Young (R)	Baron Hill (D)	Indiana is a fairly red state, but the retirement of Sen. Dan Coats has potentially put this seat into play. On the Republican side of the contest, the candidate will be three-term representative Todd Young, who brushed off a challenge from tea partier Marlin Stutzman. Young is a Naval Academy graduate, a former marine, a stellar campaigner and fundraiser, and he has the strong support of the GOP establishment, particularly Senate Majority Leader Mitch McConnell (R-KY). The U.S. Chamber of Commerce has also committed $1 million to advertising on Young's behalf. Meanwhile, the Democratic bench in Indiana is shallow, but the party was able to convince former five-term representative Baron Hill to run (while also persuading most of the less electable aspirants not to challenge him). He is a solid campaigner, but his vote in favor of ObamaCare was so unpopular in Indiana that it compelled him to hire bodyguards and ultimately cost him his seat (to Young). If Hill is to have any hope of winning, he will need the Democrats to make winning Indiana a point of emphasis (when Barack Obama did so in 2008, he was able to take the Hoosier State by one point). This is well within the realm of possibility, though even if it did happen, Hill would be the underdog. And if it does not happen, Hill will be crushed.

Iowa

Incumbent	Challenger	Notes Polls
Chuck Grassley (R)	Candidate Unknown (D)	Chuck Grassley will be 83 on Election Day, and briefly considered retirement before committing to run for his seventh term. He is very popular in Iowa, thanks in particular to his success in bringing home the pork (in a state that loves pigs), and to his custom of holding a public meeting with constituents in each of Iowa's 99 counties every year. Though the state has been trending blue, particularly in presidential years, Grassley has been impervious to such forces. In 1992, for example, Bill Clinton won Iowa by 5 points and Grassley still beat his Democratic opponent by 42. However, thanks to his chairmanship of the Senate Judiciary Committee, he is now the poster child for the GOP's controversial choice to delay considering a possible replacement for Antonin Scalia. This has caused a serious Democratic challenger to enter the race—her name, appropriately enough, is Patty Judge. Having served as Iowa's Secretary of Agriculture and Lieutenant Governor, she has name recognition and a political network. Because of her relatively recent entry into the race (March 3), she's not the presumptive nominee yet, but she's got time to rally her forces before Iowa's primaries on June 7. This race could get national attention, not only because of the potential to flip a GOP-held seat, but also as a bellwether for the impact of the Scalia issue. If obstructing Merrick Garland can bring down Chuck Grassley, it can being down just about any senator.

Kansas

Incumbent	Challenger	Notes Polls
Jerry Moran (R)	Candidate Unknown (D)	Kansas was staunchly Republican when the GOP was the more liberal party, and remained so as it became the more conservative party. The last time the state's voters sent a Democrat to the U.S. Senate, they also gave their electoral votes to an upstart governor from New York who promised a "New Deal" for Americans. In other words, Jerry Moran does not need to be worried about the Democrats, and as a proud member of the Tea Party Caucus, his right flank is also safe. A more-moderate-but-not-TOO-moderate opponent might enter the Republican primary—President Obama's second cousin Milton R. Wolf is a possibility—but this would only be a "challenge" in the academic sense of the word. Now that he is the incumbent, this senate seat is Moran's for as long as he wants it.

Kentucky

Incumbent	Challenger	Notes Polls
Rand Paul (R)	Jim Gray (D)	Kentucky has a reputation for being a solidly red state, but that's largely at the federal level. In state elections, Kentuckians often lean fairly Democratic (though that did not hold true in 2015). Rand Paul—who is only moderately popular—is vulnerable to a serious Democratic challenge, and he's got one from Lexington Mayor Jim Gray. Gray is wealthy (and so can self-fund), has a reputation for being a "straight shooter," has a small business background, and is openly gay. He thus has something of a maverick persona that actually plays quite well in the Bluegrass State. He has already "loaned" his campaign $1 million and is running ads that, shockingly, focus on his selling points, rather than his opponent's weaknesses. Paul does have weaknesses, of course; his strongly libertarian views are out of the Republican mainstream, and Kentuckians are not thrilled that he used them as his "insurance policy" against a failed presidential run. So, what should have been a safe seat for the Republicans is now looking more and more like it could be in play, though it's not quite there yet.

Louisiana

Incumbent	Challenger	Notes Polls
Candidate Unknown (R)	Candidate Unknown (D)	This race is currently up in the air. After being defeated in Lousiana's gubernatorial election, amidst a series of debilitating scandals, incumbent Sen. David Vitter announced his retirement. And the state's other nationally-prominent Republican, Bobby Jindal, is even more unpopular than Vitter. That has cleared a path for Reps. John Fleming and Charles Boustany and former Rep. Joseph Cao to enter the race. Fleming is the current fundraising champion, with just shy of $3 million in the till, and is the presumptive favorite, but that doesn't mean too much, as the dust from Vitter's decline and fall is still settling. This could be an excellent pickup opportunity for the Democrats, but the dynastic Landrieu family have all opted out, and thus far the only declared candidates are a trio of political unknowns. If DSCC chair Sen. Jon Tester (D-MT) can't pull a rabbit (or a Landrieu) out of his hat, then the job will almost certainly go to one of the three Republicans.

Missouri

Incumbent	Challenger	Notes Polls
Roy Blunt (R)	Jason Kander (D)	Roy Blunt is an incumbent, represents a solidly red state, and—though a moderate—was able to avoid a serious tea party challenge thanks to the Todd Akin "legitimate rape" fiasco in 2014. That is the good news for the Senator. The bad news? His approval ratings are among the worst in Congress, with considerably more than half of Missourians unhappy with the job he is doing. Further, the Democrats have recruited a very strong candidate in Missouri Secretary of State Jason Kander, a charismatic military veteran who is currently (at 34) the youngest statewide elected official in America (and the only one born in the 1980s). Polls currently give Blunt just a five point lead and—of far greater concern for the GOP—reveal that only one in three Missouri voters feels they know enough about Kander to form an opinion of him. His support has room to grow, then, while Blunt's largely does not. Additionally, if the Missouri governor's race is as close as expected, it could bring a higher than average number of Democrats to the polls. So too could having a candidate whose husband used to govern next-door neighbor Arkansas at the top of the ballot (In both 1992 and 1996, Bill Clinton won Missouri, making him the last Democrat to do so). The race has already turned ugly, with Kander attacking Blunt over the SCOTUS obstructionism, and painting him as a Washington insider (and thus part of "the problem") and also as a carpetbagger (largely because Blunt, who was born in Missouri, was photographed wearing a Washington Nationals cap). Blunt is still a slight favorite, but this seat is an excellent pickup opportunity for the Democrats.

New Hampshire

Incumbent	Challenger	Notes Polls
Kelly Ayotte (R)	Maggie Hassan (D)	New Hampshire is becoming bluer by the year, and though Kelly Ayotte is fairly moderate and fairly popular, the trend may catch up with her eventually. Will that be in 2016? The answer is in the hands of the state's most popular Democrat, Gov. Maggie Hassan, who decided to forego a third term as governor to mount a challenge. This compelled Ayotte to pivot toward the center, criticizing Sen. Ted Cruz (R-TX) as extremist, and also praising President Obama's climate change accord. Those statements angered many New Hampshire Republicans, and while a challenge from the right is not going to happen, some of those voters may stay home or vote third party on Election Day. Hassan has a major headache of her own to deal with, however: Rick Schubart, a former teacher at exclusive Phillips Exeter Academy, who was recently dismissed from the school for engaging in multiple acts of sexual misconduct with students. Hassan's husband was a principal at the school, and Schubart even donated money to her previous political campaigns. At best, say Republicans, the situation shows poor judgment on Hassan's part, and at worst, maybe she helped facilitate a coverup. There hasn't been a lot of polling of the race, and none since the Schubart story broke. Those polls that have been taken give Ayotte a slight lead, roughly 3 to 4 points. As with Missouri, the candidates here have already been playing political football with Antonin Scalia's replacement, which will give party leaders on both sides another reason to watch this race with interest.

North Carolina

Incumbent	Challenger	Notes Polls
Richard Burr (R)	Deborah Ross (D)	As Richard Burr tries for a third term in this purple state, his mediocre approval ratings (around 35%) have Democrats sensing an excellent pickup opportunity. However, party officials got their biggest disappointment of the 2016 campaign (so far) when former senator Kay Hagan declined to enter the race. Her decision is not terribly surprising, given the challenges of running for a Senate seat in North Carolina. To start, the state's numerous large and distinct media markets make statewide elections very expensive. Indeed, Hagan's loss to Thom Tills in 2014 was the most costly U.S. Senate contest ever, with a total of $111 million expended. In addition to the stresses of constant fundraising, it is also the case that North Carolinians like to change senators as regularly as some people change socks. In most states, after a difficult first election, a sitting senator has a huge advantage in any subsequent contest and can coast a little bit (or, sometimes, a lot). Not in North Carolina, where 13 of the last 14 Senate races have been decided by single digits, and where each of the nine senators elected between Jesse Helms in 1972 and Burr in 2004 survived for only a single term (or less). So, the Democrat won't be Kay Hagan, it will be the much less visible former State Rep. Deborah Ross, a pragmatic moderate in the mold of Hillary Clinton. Burr easily fought off a challenge from the right in the form of physician Greg Brannon, while Ross scored an equally overwhelming victory over three challengers on the Democratic side of the contest. Polls currently put Burr up by about 4 points, but that lead is likely to get smaller (or even disappear) as the DSCC steers resources toward the Tar Heel State. North Carolina is also a place where the effect of Trump could be palpable, so Burr has much reason to be nervous.

North Dakota

Incumbent	Challenger	Notes Polls
John Hoeven (R)	No Candidate (D)	John Hoeven may be the most popular politician in North Dakota, having served 10 years as governor prior to his first term in the Senate. In Washington, he compiled a voting record designed to keep constituents happy—anti-ObamaCare, anti-immigration, pro-life, pro-Keystone pipeline. North Dakota voters are not entirely averse to voting for Democrats—including their other senator, Heidi Heitkamp—but overall the state is very red. Further, the Democratic bench there is paper-thin. Consequently, there will be no challenger (the deadline for declaring passed on April 11), and the Hoevens can renew the lease on their Washington apartment for another six years.

Ohio

Incumbent	Challenger	Notes Polls
Rob Portman (R)	Ted Strickland (D)	If you look up 'bellwether' in the dictionary, you will find a picture of Ohio. The last time the state failed to give its electoral votes to the winning presidential candidate was 1960, and in the half-century since, Ohioans have split their electoral and Senate votes only twice (John Glenn/Ronald Reagan in 1980 and Howard Metzenbaum/George H. W. Bush in 1988). So, no Senate race is more likely to be affected by the presidential contest than this one—both parties will have their get-out-the-vote operations working at full capacity, and the one that is most successful may well decide whom Ohio sends to the Senate. During his first term, Rob Portman did his best to improve his reelection odds: He traveled to more than 30 countries in order to develop a reputation as a foreign policy specialist, strengthened his ties to the establishment by serving as chair of the National Republican Senatorial Committee, and banked an impressive $10 million in campaign funds. However, his approval ratings are anemic. The Democrats' candidate is former governor Ted Strickland, whom early polls give a very slight lead over Portman. Given the stakes in Ohio, and the resources that both parties will pour into this race, the outcome will likely be in doubt until the very end.

Oklahoma

Incumbent	Challenger	Notes Polls
James Lankford (R)	No Candidate (D)	Oklahoma is probably the reddest state in the nation, the only one in which Barack Obama never won a single county. James Lankford is a good match for his constituents, an arch-conservative who laments not only ObamaCare but also Medicare, who would like to shut down the EPA, and who wants to dramatically expand the Patriot Act. After winning the 2014 special election to finish Sen. Tom Coburn's unexpired term, Lankford wants a full term in his own right. He's going to get it without opposition in either the primaries or the general election.

Pennsylvania

Incumbent	Challenger	Notes Polls
Pat Toomey (R)	Katie McGinty (D)	Although Pennsylvania is the state that gave us Rick Santorum, it is actually quite blue in presidential years. Pat Toomey has been something of a mirror image of Santorum—fiscally conservative, but socially moderate. He barely eked out a victory over Joe Sestak in the Republican wave year of 2010, and so he has reason to be concerned heading into 2016. That said, Toomey will benefit from his low-key, non-confrontational nature—which Pennsylvanians like in their politicians. The Democrat will be Katie McGinty, an environmentalist with strong ties to the Clintons and to power brokers in Pennsylvania, but zero experience in elective office. With strong establishment backing, she won a bruising primary over the maverick Sestak, who was back for another go-round. If she is elected, she will be Pennsylvania's first female senator, and the Party is hoping that a Hillary Clinton-Katie McGinty ticket will attract a lot of women voters. The DSCC will go all out to make sure McGinty has plenty of resources in what will certainly be one of the highest profile Senate races. Early polls give Toomey a 10-point lead, OK but not great against an opponent with low name recognition whose support still has room to grow.

South Carolina

Incumbent	Challenger	Notes Polls
Tim Scott (R)	Thomas Dixon (D)	South Carolinians like their Senators ultra-conservative and Tim Scott, who was appointed (and then elected) to finish Jim DeMint's unexpired term, fits the bill. A devout evangelical Christian, Scott strongly opposes Iran, abortion, ObamaCare, labor unions, and earmarks for 49 of the 50 states (the $300 million for dredging Charleston's harbor, he argued, was about job creation and not pork). The lone Democrat to declare is Thomas Dixon, a pastor and activist who co-founded The Coalition: People United to Take Back Our Community. He is also a political novice who acknowledges being an alcoholic and drug addict, and who has spent time in prison. There may be states where that would not be a deal-breaker (Nevada?), but South Carolina is not one of them. This one is about as safe as it gets for the GOP.

South Dakota

Incumbent	Challenger	Notes Polls
John Thune (R)	Jay Williams (D)	The state that was home to liberal three-term Democratic senator and presidential candidate George McGovern, as well as more recent three-term Democratic senators Tom Daschle and Tim Johnson, is now deep red. So much so, in fact, that John Thune ran unopposed in 2010. The Democrats are stuck with political neophyte Jay Williams, who—when he announced his intention to run—explained that he's very qualified for office because he has a degree in political science. Williams is going to get crushed, of course.

Utah

Incumbent	Challenger	Notes Polls
Mike Lee (R)	Jonathan Swinton (D)	Mike Lee did not face a primary challenge and his Democratic opponent is Jonathan Swinton, a marriage and family therapist and a political novice. Swinton's slogan is, "Washington Needs a Marriage Counselor," which is probably true, but not the stuff of electoral victories. Former Rep. Tim Matheson might have given Lee a run for his money, but in avoiding that challenge, Lee wrote his ticket for another six years in Washington. He will win this one by 30 or 40 points.

Wisconsin

Incumbent	Challenger	Notes Polls
Ron Johnson (R)	Russ Feingold (D)	Ron Johnson won a close election over Russ Feingold in 2010 (51% to 47%) and then served a fairly lackluster first term. He has particularly been hurt by his highly publicized confrontation with Hillary Clinton during the congressional hearings on Benghazi, and also by his propensity to shoot from the hip. Among other impolitic moments, he has suggested that those who take out student loans are lazy, those who utilize ObamaCare are moochers, and has referred to American Muslims as "those people." Johnson's opponent is Feingold, who will attempt to become only the second senator in history to reclaim his seat in a rematch (the first was Peter Gerry of Rhode Island, who lost his reelection bid in 1928 but came back to defeat GOP senator Felix Hebert in 1934). Feingold has has some pretty serious baggage of his own, however. Having made a name as a campaign finance reformer, he declined most outside funds in 2010. Though perhaps a sincere gesture, this crippled his campaign and contributed substantially to his defeat. Now, Feingold will accept that money, which will be helpful on a practical level but will also open him up to charges of hypocrisy. In addition, after leaving office, the PAC that Feingold founded—Progressives United—appears to have spent considerably more money on Feingold's salary and on buying copies of his book to give out as "gifts" rather than actually lobbying for progressive causes. Given all the ammunition being provided by the candidates, along with the fact that Wisconsin is a particularly polarized purple state, this will be an ugly campaign. The mudslinging has already started, in fact—the Republicans are lambasting "Radical Russ Feingold" on their state party website, while the Democrats are pointing out on their site that one of "Out of touch" Ron Johnson's donors is a white supremacist slumlord. Polls currently put Feingold up by about 6 points, and the Democrats will do everything they can to keep it that way, as this state is essential to their chances of taking the Senate back.