Anything to split up the vote. They know this guy is a charmer and knows how to work a crowd. They would love him to play spoiler to get a more moderate GOP nominee.
They are pushing him hard, as his constituency of evangelicals and home schoolers will otherwise probably go for Sarah...and they are hoping he will split enough off to knock her out...making room for Romney.
Not going to happen, although he still has a devoted following of huckahillbillies here in Iowa.