GOP voters in Maryland, Washington, D.C., and Wisconsin go to the polls Tuesday, but with Mitt Romney expected to glide to double-digit primary victories in D.C. and Maryland, all the drama centers around the Badger State. Most recent Wisconsin polls show Romney with a high-single-digit lead over Rick Santorum, though the Pennsylvanian predicts that he may "sneak in and have an upset." To help him get there, Santorum is going all in with the "political equivalent of the nuclear option": A TV ad with President Obama's face morphing into Romney's. If Santorum falls short in Wisconsin, will his increasingly long odds and mounting pressure from the GOP establishment convince him to quit the race?

Wisconsin is the end of the line: Santorum is talking tough, says Paul Steinhauser at CNN. But with Romney racking up delegates and big-name endorsements, Wisconsin is pretty clearly Santorum's "final chance to convince Republicans that the race for the GOP nomination isn't over." If he loses, the next contests aren't until April 24, and he's poised to lose all five of them, including his home state, Pennsylvania. He'll drop out before imperiling his bright political future with a humiliating Keystone State loss.
"Wisconsin primary looms large for Romney, larger for Santorum"

This won't be "Santorum's Waterloo": The GOP political class "badly wants the primary to be over," but Republican voters don't, say Chris Cillizza and Aaron Blake at The Washington Post. Neither does Santorum, judging by his "dogged refusal to talk endgame." Barring a huge — and highly unlikely — Romney blowout, it's "tough to imagine a scenario by which Wisconsin brings a formal end to the contest."
"Wisconsin primary: Rick Santorum's Waterloo?"

Besides, GOP voters deserve a longer race: Things are looking pretty bleak for Santorum now, says Walter Shapiro in the Columbia Journalism Review. But reporters and pundits shouldn't "start pulling out the tent pegs while Santorum is still performing under the Big Top." As long as "Santorum is still running for president for real," Republican voters in big states like Texas, New York, and California deserve to have their say, and shouldn't be "effectively disenfranchised" by an impatient GOP establishment and "smug" press corps.
"Why is the press so ready to count Santorum out?"