Dem
51
GOP
49
In 2020, the early Democratic primaries (before Super Tuesday), covered 27 days. This went from the messy and inconclusive Iowa caucuses, where no one knew who won for weeks, through New Hampshire, Nevada, and finally South Carolina, where Joe Biden won decisively and consolidated his support heading into super Tuesday.
This time, the Republicans are going to take much longer to get through Part I. It will be 41 days from Iowa (on Jan. 15) to South Carolina (on Feb. 24). There will also be 51 days between Iowa and Super Tuesday, historically an unusually long time. This will be the longest early phase since 2008, when Nevada became an early state. It will also feature some long breaks between contests. Among other possibilities, it could make candidates who can't fundraise after early defeats drop out and allow the opposition to Donald Trump to consolidate around one person.
Iowa and New Hampshire always go 1 and 2, with 8 days between them because the caucuses are always on a Monday and the NH primary is always on a Tuesday. After those there will be a 16-day break when candidates, donors, and pundits can take stock of the situation. A lot could happen in those 16 days of dead time. If Trump wins commanding victories in Iowa and New Hampshire, these 16 days could see everyone else drop out and end the race right then and there. However, if Trump loses (or almost loses) one of those two, the 16 days could be filled with pleas from many Republicans for everyone except the top Trump challenger to get out.
The caucuses and primaries are not independent. After Iowa, New Hampshire voters take account of it and may change their planned vote as a consequence of what happened in the middle of the country 8 days earlier. After New Hampshire, there will be a long period when the race could consolidate as megadonors and the media take time to assess the situation. Candidates on a downward trajectory could be forced out. Candidates on an upward trajectory will get massive media coverage for over 2 weeks. That could help or hurt, depending on how they handle it. For example, if Nikki Haley were to win New Hampshire after Trump won Iowa, the 16-day gap would give donors and party leaders more time to pressure Gov. Ron DeSantis (R-FL) to drop out and endorse Haley. On the other hand, some of the later states have a rule that if no candidate gets over 50%, the delegates are divided proportionally but if someone is over 50%, that candidate wins all the marbles. If DeSantis and Haley are equally viable, it might be better for the anti-Trumpers to have both of them stay in to keep Trump under 50%. After New Hampshire there will be time to think about this. In short, the long gaps between contests could have effects we can't foresee now. (V)