Gretchen's Take: What Wisconsin shows about crossover voting

Two polls out of Wisconsin this week show a big change for the GOP.

Cruz out in front by 10 points over Trump in the Marquette poll and now in the Fox News poll too. One other important number. In the Marquette poll, 8 percent still don't know who they’ll choose.

That 8 percent could end up deciding who wins on Tuesday. Wisconsin is also an open primary meaning democrats and independents may vote republican.

Also, in the Marquette poll, 5 percent of Democrats say they'll cross over to the GOP, and independents say they’ll choose the Republican primary over the Democratic one 60 to 40 percent.

Conventional wisdom says Trump benefits from those cross-over votes, but then there’s Governor Scott Walker’s endorsement. Walker remains very popular in his state at 80 percent approval among Republicans – and he’s endorsed Ted Cruz.