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WASHINGTON -- Democrat Hillary Rodham Clinton said Sunday she might be willing to garnish the wages of workers who refuse to buy health insurance to achieve coverage for all Americans.

The New York senator has criticized presidential rival Barack Obama for pushing a health plan that would not require universal coverage. Clinton has not always specified the enforcement measures she would embrace, but when pressed on ABC's "This Week," she said: "I think there are a number of mechanisms" that are possible, including "going after people's wages, automatic enrollment."

Clinton 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. With her proposals for subsidies, she said, "it will be affordable for everyone."

Clinton also suggested that Obama would be more susceptible to Republican attack ads in a general election because he has not been scrutinized for years as she has.

"I've been through the Republican attacks over and over again," she said. When Obama was elected to the Senate from Illinois in 2004, she said, he "didn't face anyone who ran attack ads" comparable to those aimed at her.

The presidential contenders in both parties campaigned all-out on Sunday, two days before the Super Tuesday voting in 24 states holding primaries or caucuses.

Clinton was campaigning in Missouri and Minneapolis. Obama scheduled a rally in Wilmington, Del., while some of his highest-profile surrogates — his wife, Michelle, Oprah Winfrey and Caroline Kennedy — were rallying voters in Los Angeles. Among Republicans, Arizona Sen. John McCain was stumping in Connecticut and former Massachusetts Gov. Mitt Romney scheduled stops in Glen Ellyn, Ill., and the St. Louis suburb of Maryland Heights. Former Arkansas Gov. Mike Huckabee was concentrating on the South, with appearances in Georgia and Tennessee.

McCain told "Fox News Sunday" he would veto any tax increase passed by a Democratic-controlled Congress. McCain, who opposed President Bush's first two tax cuts, now says Congress should make the reductions permanent, and that there also should be further tax reductions for business investments.

His chief rival, Romney, told the ABC program that McCain "doesn't understand the economy" and that his advocacy of a higher gasoline tax to combat global warming would hurt U.S. consumers.

Romney also called on Huckabee to drop from the race. In response, called the suggestion "ludicrous," noting that only a fraction of the delegates needed to win the Republican presidential nomination had been apportioned thus far.

"I've got a different take on that. I think it's time for Mitt Romney to step aside," Huckabee said on CNN.