The beautiful thing about Wisconsin primaries is that everyone is on the same ballot. This was one of Robert "Fighting Bob" La Follette's innovations, and it basically drives pollsters mad. I can guarantee you that there are serious people in Wisconsin right now making a serious decision between Huckabee and Obama.
In 1960, Wisconsin broke for John F. Kennedy in the primary over Minnesota's Humphrey. Wisconsin Catholics were the crucial swing voters, as they were in the general election against Richard Nixon in Wisconsin. In 2008, of course, none of the candidates are Catholic: Clinton and McCain can be described as High Church Baptist, but aren't regarded as especially devout; Obama belongs to the inoffensive United Church of Christ, yet many people still believe he's a Muslim; and Huckabee is a Southern Baptist, of the sort which not long ago called the Church of Rome the Whore of Babylon. He's not going to pick up many conservative Catholic votes... and before anyone asks, the following is the conservative Wisconsin Evangelical Lutheran Synod's policy:
We cannot ask candidates with no religion to affirm a belief in God as a condition of running for office. If any candidate agrees to such a test, it will be used against all religious candidates -- Jews, Catholics, Lutherans, everyone, even against non-religious candidates. If we do not speak up against these tests, we are opening the door to divisive anti-religious campaign techniques that destroy the principles of civil discussion that have been the basis for American democracy. People of all religions or of no religion should speak up against such religious tests for public office.Anyway. Clinton has done well with Catholics in past primaries, but I tend to think this is a demographic accident of having various machines on side in New York, in Massachusetts, and in southern California. At any rate, Milwaukee's mayor (and presumably its associated machine) has endorsed Obama. There isn't a large Latino population in Wisconsin, and most of it is made of recent Mexican immigrants by way of Chicago. There is the rather conservative northeast part of the state, and it's not a coincidence that McCain and Huckabee are both touring Appleton, Joe McCarthy's home town. (Actually it's Grand Chute, but I think the old farm is now underneath a parking lot.)
Finally, watch the media chatterers get the names wrong. A Wisconsin pronunciation guide can be found here.