Sen. Tim Johnson (D-SD) will retire at the end of this session of Congress, creating an open seat in South Dakota for the first time since 1978. It will be tough for the Democrats to hold the seat in very red South Dakota. Johnson cited his age in his announcement but he suffered a stroke in 2006 and has not fully recovered from it. In 2008 he was reelected to the Senate with a big sympathy vote. But that works only so long. Besides, 2008 was a Democratic wave year and 2014 will not be.
The Democrats are now hastily looking for someone to replace Johnson. Two potential candidates are his son, Brendan Johnson, a U.S. attorney, and Stephanie Herseth Sandlin, a former U.S. representative. Neither has announced yet and both will probably test the waters first.
Former governor Mike Rounds (R) is a candidate for the seat but is likely to be opposed by a tea party candidate. This could lead to a bloody ideological battle. Nevertheless, in such a red state, any Republican has to be regarded as the favorite.