WASHINGTON (AP) -- The top presidential candidates and their big-name supporters campaigned from coast to coast Sunday, but one contender seemed atop everyone's mind: Hillary Rodham Clinton.
Republicans John McCain and Mitt Romney contrasted themselves, and each other, with Clinton as though she were the nominee. Her Democratic rival, Barack Obama, played along to a degree, saying Clinton is so polarizing that he is their party's better bet.
Rather than diverting the less-than-flattering attention, Clinton embraced it.
"I've been taking the incoming fire from Republicans for about 16 years now, and I'm still here, because I have been vetted, I have been tested," she said in a TV interview before campaigning in Missouri and Minneapolis.
"There's unlikely to be any new surprises," Clinton added, implying the same cannot be said of Obama, who has been in Congress three years.
Her confidence notwithstanding, polls showed Obama narrowing the lead that Clinton has enjoyed among Democrats nationwide, even as McCain appeared to be pulling away from Romney.
With 24 states holding presidential contests Tuesday, Sunday was an intense day of campaigning and advertising, making it all the more remarkable that one figure managed to dominate so much of the talk and speculation.
For years the New York senator and former first lady has been an object of fascination, mystery and sometimes scorn by Americans, few of whom seem neutral toward her. She is the Democrat conservatives most love to hate, and McCain and Romney campaigned against her Sunday as if in a proxy battle against one another.
"If we want a party that is indistinguishable from Hillary Clinton on an issue like illegal immigration," Romney said, "we're going to have John McCain as a nominee. That's the wrong way to go."
McCain, campaigning in Fairfield, Conn., said he has never sought special projects for his state, and added: "In her short time in the United States Senate, the senator from New York, Senator Clinton, got $500 million worth of pork barrel projects. My friends, that kind of thing is going to stop."
The Clinton fascination is trickier for Obama. He wants to capitalize on Republicans' opposition to her without agreeing that she is the inevitable nominee.
Speaking on CBS' "Face the Nation" before campaigning in Delaware, the Illinois senator said the problem is "not all of Senator Clinton's making, but I don't think there's any doubt that the Republicans consider her a polarizing figure."
Obama drew an impressive crowd of 20,000 in downtown Wilmington, but his campaign attracted attention in other places, too. It said he would air a TV ad during the Super Bowl, an expensive time slot, in two dozen states with presidential contests this month. And at a Los Angeles event, his stand-ins were his wife, Michelle, TV star Oprah Winfrey, and Caroline Kennedy, daughter of President Kennedy.
They were joined by, Maria Shriver, the wife of California Gov. Arnold Schwarzenegger, who followed in the steps of Caroline and their uncle, Sen. Edward M. Kennedy, in endorsing Obama.
"I thought, if Barack Obama was a state, he'd be California," she said to a crowd of 9,000 inside UCLA's Pauley Pavilion. "Diverse, open, smart, independent, bucks tradition. Innovative. Inspirational. Dreamer. Leader."
Winfrey bridled at criticism she received after her first campaign foray for Obama in three early voting states.
"You know, after Iowa, there were some women who had the nerve to say to me, 'How could you? How could you?'" she said, with mock indignation. "'You're a traitor to your gender.'"
The crowd booed.
"Yes, that's how I feel," she said, adding a little later, "I say, I am not a traitor. No, I'm not a traitor. I'm just following my own truth, and that truth has led me to Barack Obama."
As usual, another prominent Clinton - the candidate's husband and former president - was in the thick of things.
Bill Clinton visited four churches in mostly black sections of Los Angeles. The trip was widely seen as a bid to smooth over perceptions that he had injected race into last month's Democratic primary in South Carolina, which Obama won handily.
The former president never mentioned Obama by name when he spoke for about 20 minutes at the City of Refuge church in Gardena. But he struck a conciliatory tone in describing this year's Democratic contest as "an embarrassment of riches."
"I'm not against anybody," Clinton said.
Campaigning in a western suburb of Chicago, Romney took a swipe at Obama, again as a means of nicking McCain.
"Yesterday Barack Obama said there's not a dime's worth of difference between he and Senator McCain on illegal immigration," Romney told a crowd at the College of DuPage. "I'm afraid it's going to be real hard to win the White House if there's not much difference between our nominee and theirs, and that's why I'm going to make sure that we stand for Republican ideals and win the White House on that platform."
Later, in suburban St. Louis, former Sen. Rick Santorum of Pennsylvania, a favorite of conservatives, endorsed Romney during a Super Bowl party.
"Mitt Romney is hitting his stride. He is speaking with clarity, with conviction, with the heart and the mind together, which is what conservatives want to hear," said Santorum.
McCain largely shrugged off such jibes, although he said he is "much more conservative" than Romney.
He told reporters that despite polls showing him with a 20-point lead over Romney, "I'm incredibly nervous, and I've seen that movie before." Knocking twice on a wooden table in his campaign bus, he said, "a lot of this business is expectation levels, so it's our job to keep our own expectation levels down."
A third GOP candidate, former Arkansas Gov. Mike Huckabee, struggled for attention and rejected suggestions that he step aside.
"I'll stay in until someone has 1,191 delegates," he said in a telephone interview with The Associated Press from Kennesaw, Ga., referring to the number of convention delegates needed to secure the party nod. "A year ago, nobody said I'd still be here. Look who's still on his feet."
In a day dominated by familiar stump speeches, Hillary Clinton made news by saying she might allow workers' wages to be garnisheed if they refuse to buy health insurance. She has criticized Obama for pushing a health plan that she says would not require universal coverage.
Pressed on how she would enforce her mandate, Clinton said: "I think there are a number of mechanisms" that are possible, including "going after people's wages, automatic enrollment."
She said such measures would apply only to workers who can afford health coverage but refuse to buy it, which puts undue pressure on hospitals and emergency rooms. Under her plan, she said, health care "will be affordable for everyone" because she would limit premium payments "to a low percent of your income."
Obama has said he would require parents to buy health insurance for children, and possibly fine them if they refused. But he would not insist that all adults buy insurance.
Associated Press writers Michael R. Blood and Laura Kurtzman in Los Angeles, Libby Quaid in Fairfield, Conn., Glen Johnson in Glen Ellyn, Ill., Mike Glover in St. Louis and Liz Sidoti in Washington contributed to this report.
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