Nate Silver has a good post up on the NYT about what Huckabee’s decision not to run means for the Iowa caucuses.

ad Mr. Huckabee won Iowa again, a plausible narrative might have emerged that he was a one-state wonder. Other candidates with strong social-conservative or religious credentials, like Pat Robertson in 1988 and Pat Buchanan in 1996, performed strongly in Iowa but did not gather any particular momentum from it. The same was true of Mr. Huckabee in 2008, of course — he finished a distant third in New Hampshire and failed to win any states outside the South except Kansas.

That narrative may not have been entirely fair to Mr. Huckabee. Against what is probably a weaker field this time around, he would have had a pretty good chance of becoming the nominee. Still, with every other candidate trying to spin the story and diminish the importance of a Huckabee victory in Iowa, the narrative could have provided some cover. Now the rest of the field will have fewer excuses for a losing performance in the state.

The tl:dr version is that socially conservative voters actually gain clout with Huckabee out of the race.