WAUKESHA, Wis. — Pushing forward off the momentum from his electoral victories, Sen. Barack Obama looked past his Democratic challenger on Wednesday and directed his criticisms increasingly toward Republican presidential frontrunner Sen. John McCain.

"It's clear he knows who his opponent is going to be," the Illinois Democrat said, campaigning in advance of Tuesday's Wisconsin primary. "I'm looking forward to a great debate on the issues with John McCain."

Associated Press (ENLARGE)

Sen. Barack Obama is expected to take most of Thursday off in Chicago, before taking his wife out for Valentine's Day dinner.

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On a day when Obama focused on pocketbook issues, he suggested the Arizona senator had lost his way after first opposing tax cuts pushed by the Bush administration, before reversing course.

"Somewhere along the line, he traded those principles for his party's nomination," Obama said, adding later that McCain would be the "same as we've had the last seven years."

Earlier, McCain said Obama has run a good campaign, but one "singularly lacking in specifics."

In a possible Freudian slip, Obama at one point here seemed to project himself already in the White House.

"After a year in office," Obama said, quickly correcting himself. "Jumping ahead there. Jumping ahead. After a year of campaigning ... my bet has paid off because the American people are responding all across the country."

If McCain was a target, so was Sen. Hillary Clinton of New York, who campaigned in Texas, a state now viewed as essential for her campaign. Texas and Ohio vote on March 4.

Obama questioned Clinton's past support of the North American Free Trade Agreement during an economic speech at a General Motors assembly plant in Janesville, Wis., where a new round of job cuts was announced Tuesday.

"In the years after her husband signed NAFTA, Sen. Clinton would go around talking about how great it was," Obama said. "Now that she's running for president, she says we need a time-out on trade. No one knows when this time-out will end. Maybe after the election."

Clinton, meanwhile, told reporters Obama's policy proposals would fail to provide universal health care or turn the economy around. "We need real results, not more rhetoric," she said.

In San Antonio, where she is counting on support from a city with a Latino population of about 60 percent, Clinton ridiculed Obama's mantra of change.

"Change is going to happen anyway," she told several thousand people at St. Mary's University. "The question is not whether or not we will have change. The question is whether or not we will have progress that makes a difference."

Both Democrats also battled over whether it is still mathematically possible for Clinton to win the nomination.

"For her to make progress on the pledged delegate front, she has to win blowouts," Obama campaign manager David Plouffe said.

After Tuesday, Obama leads among pledged delegates. He also leads in the overall total that includes so-called superdelegates free to make their own decision at the national convention.

Still, Clinton's campaign said the former first lady should not be written off.

"Hillary leads in the three largest, delegate-rich states remaining: Texas, Ohio and Pennsylvania," Clinton strategist Mark Penn wrote in a memo to reporters.

Penn pointed to Clinton's husband as a lesson in history. "The Democratic nomination goes to the candidate who wins the most delegates — not the candidate who wins the most states," he wrote.

Clinton also launched a new TV ad in Wisconsin, where she is expected to campaign this weekend. The ad suggests Obama is dodging a formal debate in the state. "Maybe he'd prefer to give speeches than have to answer questions," the ad says.

Obama picked up the backing of David Wilhelm, a former Democratic National Committee chairman who managed Bill Clinton's winning 1992 presidential campaign. Wilhelm, now a venture capitalist in Ohio, has longstanding ties to Obama's top adviser, David Axelrod.

The Obama campaign also announced an endorsement from the governor of Puerto Rico, which on June 7 is the last entity to hold a Democratic nominating contest.

Reflecting some confidence, Obama is expected to take most of Thursday off in Chicago, before taking his wife out for Valentine's Day dinner.

During a Chicago visit Wednesday, Democratic Party chairman Howard Dean defended his party's nominating process, including having some convention votes not tied to state primary or caucus outcomes.

"The superdelegates are ordinary Americans who are elected by the same people who elect candidates," the one-time presidential candidate said.