I thought I would indulge in a little excessively early prognostication. With Governor Huckabee declaring his non-candidacy, that leaves the field open. The conventional wisdom among many is that Mitt Romney is incapable of winning the Republican nomination because he's Mormon and is "soft" on Obama-care. I think Romney is the guy to bet on getting the nomination and here is why...
First, there is a long history of the GOP nominating the guy who has the "resume." If the Democrats picked nominees like the GOP did, the 2008 contest would have been between Clinton and Edwards with Obama having to wait for a VP offer - assuming he could hang around longer than Richardson. But Republicans LOVE to pick the resume. The often nominate the runner up from the previous election cycle. Examples: Reagan lost to Ford in 1976 and was nominated in 1980. GHW Bush lost to Reagan in 1980 and was nominated in 1988. Bob Dole was Ford's running mate in 1976 and lost the nomination to GHW Bush in 1988 but was nominated in 1996. John McCain lost the nomination to GW Bush in 2000 but had a come back win to get the nomination in 2008. So who came in "second" in 2008? It depends how you figure it. Romney was probably the second most serious candidate but Huckabee hung on like grim death to come in second in the delegate count even though he was mathematically eliminated. So the "who's turn is it" question would be open to interpretation with both Romney and Huckabee in the race. With Huckabee out, Romney is in sole command of the "best resume" title for 2012.
In addition to the "tradition," the GOP nomination process is more dependent on "winner take all" results. So if a candidate comes in first in a crowded field but with only 25% of the vote, that candidate could walk away with 100% of the delegates for that state. So being out in front is huge. The early polls show that only Romney and Huckabee were consistently getting close to 20% of support from Republican respondents (see polls here). Romney and Huckabee were also the most popular "second choice." So with Huckabee gone, that sets up Romney.
Then there are the delegates who get to vote at the convention independently from the primary and caucus results. Democrats call these "super delegates." Republican use them too. This crowd is the "Party establishment" that the tea party dislikes so much. These are also the people who occasionally leaked out "Palin is an idiot" stories in the aftermath of the 2008 election catastrophe. I hardly think these people are going to line up behind either Palin or Trump. They'd be torn between a couple of former governors with decent records in office but not when the choice is between one of them and cluster of whackos, anti-establishment demagogues and unknowns. Gingrich MIGHT attract some of this support but his tenure as Speaker was controversial among the Republican establishment. Also, Gingrich's infamous relationship with his family(ies) makes the Mormon Romney look good to evangelicals, at least the elite ones, by comparison.
This sets up Obama vs Romney in 2012. It also takes the health care reform issue off the table for things Republicans can challenge Obama on. That could be huge as this was the main issue Republicans used to win seats in 2010. Romney's close ties to the auto industry might make it hard for him to go after Obama on the stimulus because a big part of the post 2010 bail out/stimulus was directed at keeping the US auto industry afloat. On foreign policy, Romney can hardly make a serious claim that he's got more or more hawkish foreign policy credentials than the incumbent president who "got Bin Laden." His best bet would be run against the idea of foreign policy and portray himself as something of an isolationist (which is what Ron Paul is doing).
All of this makes me think that the biggest beneficiary of Huckabee's non-candidacy is going to be Obama.