The following is an explanation for why each candidate did (or didn't) improve his chances of winning the nomination now that Huckabee is no longer a contender:
No one candidate got a big bounce from Huckabee's exit. Huckabee was leading the polls in Iowa and South Carolina, which presumably helps whomever is in second place there. The problem? There is no clear second place in those states. (See all the early state primary polling on the Primaries page.) There is also no "Huckabee Jr." candidate who will step exactly into his shoes. Instead, many candidates will benefit a little.
Christie +2% -- He benefits from any sense that there is a vacuum in the field. Huckabee's departure also removes an obstacle from Iowa, where Christie will need to prove he is not over-hyped. But other candidates will move in to fill the void. Christie's role is to be the one candidate who can unite the Tea Party and Republican establishment; Huckabee never played the role.
Romney +2% -- Though Romney is not interested in Iowa or South Carolina as much, Huckabee's absence lessens the possibility that the same person will with both states. This makes a New Hampshire strategy a bit more viable. There's little overlap between the Romney and Huckabee constituencies, but without Huckabee in the race, it's easier for Romney to claim the mantle of "next in line." Also, Romney will perform better in the IA and SC polls now, though it may be an illusion based on his name recognition.
Daniels +2% and Pawlenty +3% -- These two candidates were behind Huckabee in Iowa and each have high electability. Neither is objectionable to the Iowa voters and can at least claim to be serious candidates. Arguably, they benefit the most from Huckabee's departure. However, they are fighting over the same oxygen, and the gain is split between them. Pawlenty gets a slight edge because Huckabee's social conservatives may be wary of Daniels' earlier gaffe about a "truce" on social issues (see this earlier post).
Cain +2% -- Though much further down in the polls and perceived electability, Cain benefits because he shares some attributes with Huckabee that might help him pick up the pieces: He's a populist, Southern, rhetorically-gifted outsider who will rely on the debates to create campaign buzz. Without Huckabee above him on the poll list, it will be that much easier for Cain to get invited to the primary debates.
Palin +1% -- Like Huckabee, she is somewhat popular among evangelical Christians and needs to win Iowa. But Huckabee's supporters already had the option of moving over to Team Sarah and had not chosen to do so.
The following candidates do not receive an increase in their chances of winning the nomination:
Gingrich -- He may be fooled into thinking he should spend his resources in Iowa, but the reality is that social conservatives there will not accept him. He will need to rely on a New Hampshire strategy.
Trump -- Trump will also need to rely on a New Hampshire strategy.
Santorum -- In theory he should be able to attract Huckabee's social conservatives, but they will tend to gravitate toward someone with a higher profile.
Paul -- He has his own constituency and is unlikely to broaden it regardless of who drops out of the race.
