Former Pennsylvania Senator Rick Santorum verbally circled April 24 (the Pennsylvania primary, 71 delegates at stake) and May 29 (the Texas primary, 155 delegates at stake) on his nomination calendar Tuesday night in his speech to supporters. But those goals fail to reflect the reality that he has now slid into irrelevancy in the race.

Perhaps the most important words from the Santorum camp Tuesday night came not from the candidate, but from his senior strategist. "We think regardless of results today, Pennsylvania becomes the make-or-break state for both candidates," John Brabender told the Washington Post's Chris Cillizza.

That certainly invites the Romney campaign and its Super PAC allies to unload a ton of cash to dominate the TV airwaves in the Keystone State in hopes of delivering a knockout punch on April 24. A Quinnipiac University poll out this week showed Santorum's lead in his home state has dwindled down to six points as he heads into a three week stretch without any debates or intervening primary nights to inject new momentum into his bid.

[Related: Wisconsin, Maryland voters still mixed on GOP nominee]

However, after Romney's clean sweep in Wisconsin, Maryland and Washington, D.C., on Tuesday, a Santorum knockout is not required for Romney to take on the role of presumptive Republican nominee. And both Romney and President Barack Obama have shifted their attention, and their rhetoric, to November.

For all the positive talk from Romney about his private sector experience and Obama's boastful ticking through his first-term accomplishments before adoring and financially generous Democrats at fundraisers around the country, it became clear this week that the beginning stages of the general election battle will be largely presented through the negative frames each side is building around the other.

Romney has put forth a three-pronged characterization of President Obama aimed at sowing serious doubt among Americans about his stewardship of the country. In Romney's telling, President Obama is an enemy of business and free enterprise willing to pile on more debt to fund a larger federal government, a failed leader who constantly attempts to assign blame for the country's economic woes, and (in an act of political jujitsu) a man who has lost touch with most Americans.

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[Related: Obama assails Ryan budget as 'thinly veiled social Darwinism']

"It's enough to make you think that years of flying around on Air Force One, surrounded by an adoring staff of True Believers telling you what a great job you are doing, well, that might be enough to make you a little out of touch," Romney said last night in Milwaukee.

Romney's personal wealth has been a major target for the Obama campaign and its allies, who paint him as a candidate unable to relate to middle class Americans. In his Tuesday victory speech, Romney made clear he had no plans of ceding that ground to the president.

For his part, President Obama used his speech before publishers and editors at the annual Associated Press conference in Washington, D.C., Tuesday to frame Romney as interested in protecting the privileged class with lower taxes at the expense of decimating government programs upon which the elderly and the low-income rely and investments in education, energy and infrastructure.

"So we tried this theory out. And you would think that after the results of this experiment in trickle-down economics, after the results were made painfully clear, that the proponents of this theory might show some humility, might moderate their views a bit," President Obama said. "But that's exactly the opposite of what they've done. Instead of moderating their views even slightly, the Republicans running Congress right now have doubled down, and proposed a budget so far to the right it makes the Contract with America look like the New Deal," he added, and then went on to tie Romney to the House Republican budget.

[Related: Palin's advice for Romney: Don't be afraid to go 'rogue' with VP choice]

The Obama team has made clear it has no intention in letting up on the caricature of Romney as a car-elevator-owning, offshore-account-possessing man so rich he couldn't possibly understand the economic plight facing most of his fellow citizens. And Romney made clear Tuesday he's just as willing to go negative on the president.

It is through those opposing negative narratives, far more than either candidate's prescriptive positive vision for the future, that the general election contest between Romney and Obama will take shape.

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