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John Kerry (search) on Sunday accused the Bush administration of an "incredible cave-in" to drug companies at taxpayer expense, citing the dramatically higher cost estimate for the new Medicare overhaul.

The administration now puts the 10-year cost of the prescription drug benefit at $534 billion. That is one-third higher than the $395 billion figure from the Congressional Budget Office (search) that administration officials and congressional GOP leaders cited as they pushed the legislation through Congress in November.

Using the Medicare figures, Kerry expanded on his campaign theme that the main beneficiary of the new drug benefit is the pharmaceutical industry.

"We learned that in their incredible cave-in to the powerful interests of the drug companies of America, they dunned the taxpayers of our nation $139 billion extra so they can line the pockets of people who contributed to their campaign," Kerry told an audience of about 600 people. "He thought you wouldn't notice what's happening."

Polls give him a 2-to-1 lead in the state, though they also show that as many as 40 percent of likely voters have yet to make up their mind.

Polls have shown Kerry with a solid edge in five of the seven states holding Democratic presidential contests on Tuesday; some 269 pledged delegates are at stake.

Kerry is running television commercials in all those states and has pledged to campaign in all seven as well. He spent most of Sunday io poltn North Dakota, which has 14 pledged delegates up for grabs.

His campaign hopes a solid showing Tuesday night will narrow the field of Democratic contenders, heading into the voting Saturday in Washington state and Michigan.

Kerry also defended himself from charges by rival Howard Dean, who said Kerry owes the country an apology for taking donations eight years ago from Johnny Chung, who later pleaded guilty to making illegal campaign contributions. Dean said Kerry lacks principle and that he is "incensed by his hypocrisy."

"He misrepresented himself, grossly misrepresented himself, as a candidate who would take on special interests in Washington," Dean told reporters aboard a flight from Milwaukee to Detroit. "We cannot go on in this country having United States senators and public officials gather their money from people who they then perform favors for."

In response, Kerry said: "My record speaks to that. I have fought powerful special interests every step of the way."

Dean also complained about reports that Kerry had collected hundreds of thousands of dollars from lobbyists during his Senate career. Kerry dismissed that complaint, saying such donations made up a tiny portion of his total fund raising. "You are talking about half of one percent," Kerry said.

The Massachusetts senator also added more endorsements Sunday. Washington's governor, Gary Locke, said Kerry's "experience and leadership skills will get our state and our country back on track."

Also, leaders of the United Farm Workers union announced their support. "He shares our vision of helping Latinos and all people achieve the decent life America promises those who work hard for a living," said the union's president, Arturo Rodriguez.

The union's executive board wanted to make its endorsement before next month's California primary, a union spokesman said.

Given his front-runner status, Kerry is spending more time focusing on President Bush and seeking to sound an optimistic theme that would fit a general election campaign.

"This election has to be about more than words," said Kerry. "It's time to have a real conversation in America, it's time to make our politics meaningful. It's time to change."

On issues from health care to job safety, Kerry warned that the odds have become tilted against working families.

"We need to make it clear that we're not going to accept this unfairness, the fundamental unfairness that's taking over in the workplace and the life of America," he said.

Kerry was gathering with North Dakota activists for a Super Bowl party and was rooting for the New England Patriots.

Later, he was heading to New Mexico and planned to cap his seven-state wing on Monday with a visit to Arizona. Kerry was making plans to go to Seattle Tuesday to await election night returns.