Santorum's only chance is for an historic upset in Wisconsin. And that is just not likely to happen. The Etch-A-Sketch is outspending him 55-1 on TV up there and it's a winner-take-all primary, so Santorum is looking at a long night (or a short one, depending on how you look at it).
After R-Money sweeps tonight, it's a long three weeks of "inevitability" talk and how R-Money has clinched the nomination. Then on the 24th, Santorum has to win his home state, where the people there already know him and kind of hate him. The other primaries are in R-Money's backyard: Connecticut and New York (Wall Street), Rhode Island (the "sewer of New England") and Delaware (The State That Gave Us Christine O'Donnell). Santorum has to win Pennsyltucky and then hope to be competitive in Delaware. Because after that, things get better for him: Indiana, North Carolina and West Virginia, Nebraska and Arkansas, Kentucky and Texas.
In early June, California probably puts the Etch-A-Sketch over the top. But the longer the Sweater Vest of the Blessed Virgin can keep this race going, the better.