Mitt Romney, left, with Rep. Paul Ryan (R-Wis.), holds bags of food at a Culver's… (Justin Sullivan / Getty…)
Yes, there are 19 states holding primaries after Tuesday, including the two biggest delegate prizes, Texas and California. But it's the three GOP contests Tuesday, and more specifically the one in Wisconsin, that likely will mark the point at which the fight for the GOP nomination ends and the showdown with President Obama begins in earnest.
That's assuming the polls prove correct and that Mitt Romney secures a victory in the Badger State, as well as the District of Columbia and Maryland on Tuesday night, of course.
If Romney doesn't stumble, break out the Etch-A-Sketch. It's time for a reset.
Not only are the Romney and Obama campaigns ready to engage one another, but increasingly the candidates themselves are primed to battle.
The first major setting for that will be in dueling speeches President Obama and then Romney will make at the Newspaper Assn. of America Conference in Washington this week.
Today, Obama will attack the House Republicans' budget written by Wisconsin Rep. Paul Ryan, who endorsed Romney last week, as a "Trojan horse" and "thinly veiled social Darwinism."
"Disguised as a deficit reduction plan, it's really an attempt to impose a radical vision on our country," Obama will say at an Associated Press luncheon, according to excerpts of his remarks released by the White House. "It's antithetical to our entire history as a land of opportunity and upward mobility for everyone who's willing to work for it – a place where prosperity doesn't trickle down from the top, but grows outward from the heart of the middle class."
A senior administration official says the president will tie the plan to his eventual opponent, describing it as the plan a Republican president would make law.
Those remarks come on the heels of Obama's attack against the Republicans' "you're-on-your-own" economic policies during a campaign speech in Vermont on Friday. Within minutes, Romney attacked the president for pursuing a "government-centered society."
On Sunday, Vice President Joe Biden continued to play attack dog against Romney, saying the former Massachusetts governor was "out of touch" with middle class concerns.
And Monday afternoon, as the Obama campaign launched its first television ad explicitly mentioning Romney by name, Romney himself was delivering a closing argument to Wisconsin voters that looked ahead to the fight with Obama.
"I think after 30 some different contests, people feel it's time for us to focus on President Obama," he told Madison's WKOW-TV, according to CNN.
Two months ago, after Rick Santorum scored a trio of victories in Colorado, Minnesota and Missouri, a three-week lull before the next nominating contests allowed the notion that Romney was a weak front-runner to fester.
Now, Romney could pull off his own trifecta, and deprive Santorum of the oxygen he needs to sustain his campaign through another three-week gap that leads to primaries in his home state of Pennsylvania as well as Connecticut, Delaware and New York -- all friendly terrain for Romney.
Santorum's campaign is eyeing May contests in states like North Carolina, West Virginia, Arkansas and Kentucky, where the voter demographics favor him.
"If I thought that prolonging this race was a detrimental thing for our chances to win in the fall, I may -- I would take a different course. But I don't," Santorum said Monday.
An April sweep by Romney could make those moot, and by then Santorum could find himself a mere backdrop, determined but unable to derail the matchup voters will face, Obama versus Romney.
Kathleen Hennessey contributed to this report.