I think that Wisconsin is probably closing up a bit. It won't be enough for Santorum though.
Possible, but PPP's Wisconsin weekend poll gives Romney +14% among Republicans and Santorum +%5 among dems/indes and assumes they will make up 40% of the vote in the state. If democrats don't show up to vote in the GOP primary in the numbers PPP predicts as I don't think they will then Romney wins the state by double digits.
At this stage in the game I just don't see dems having anywhere near the same kind of desire they did back in Feb. to come out and vote for Santorum to mess with the GOP primary results even if they would like that to happen its one thing to say it to someone who calls its another to actually go to the polls to help make it happen.