President Bush, on a full-force offensive against presumptive Democratic rival John Kerry, is painting the Massachusetts senator as someone who waffles on national security issues and "is trying to have it both ways" on matters of intelligence.

"My opponent clearly has strong beliefs, they just don't last very long," Bush said during a re-election fundraiser in Dallas on Monday. The president also criticized Kerry's shifts in position on the Patriot Act (search), trade legislation and an education reform bill.

Bush's comments came on the eve of the latest batch of primary contests in the South.

Democratic voters in Florida, Louisiana, Mississippi and Texas will go the polls Tuesday. Kerry virtually has his party's nomination in grasp and is expected to have a clean sweep.

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Kerry has been campaigning in Florida and is sharply criticizing the Bush administration's foreign and domestic policies. During a campaign stop in Hollywood, Fla., Kerry used humor to blast Bush.

"This is my idea of spring break … I remember spring break… you lay back and do nothing," Kerry said. "The only place you can do that now is on the Bush economic team."

Bush, campaigning in his home state of Texas, continued his attacks on Kerry's Senate voting record.

Bush contrasted the New Englander's oft-stated support for intelligence gathering as a crucial component of the war on terror with his support -- two years after a deadly 1993 bombing at the World Trade Center (search) -- for cutting intelligence funding by $1.5 billion.

"Once again, Senator Kerry is trying to have it both ways. He's for good intelligence, yet he was willing to gut the intelligence services," Bush told 1,100 donors at a Houston event that raised $1.5 million for his campaign. "And that is no way to lead our nation in a time of war."

The salvo was the result of a methodical mining by the Bush campaign of the long trail of votes and speeches from Kerry's 19 years in the Senate.

Kerry's campaign said Bush's accusations have no merit and are misleading.

Advisers to Bush are focusing on national security and terrorism in hopes of bolstering their claims that Kerry would be a weak wartime leader who can't stick to one position. The president's team also aims to capitalize on poll results showing those are Bush's strongest areas with voters.

Bush held a more than 20-point lead over Kerry, 57 percent to 36 percent, among voters who were asked which one would do a better job prosecuting terrorism, according to an ABC News-Washington Post poll of 936 registered voters released Monday. The poll was taken March 4-7 and has a margin of error of plus or minus 3 percentage points.

According to a recent Gallup poll, 82 percent of Americans believe international terrorism is the critical issue this year.

Bush said a 1995 Kerry bill to cut intelligence funding was "so deeply irresponsible that he didn't have a single co-sponsor in the United States Senate," drawing laughter from the GOP crowd.

The bill would have cut $300 million from the intelligence budget over five years. The measure never made it to a floor vote and Bush cast it as evidence that Kerry is unfit to lead the nation during a war on terror.

Yet, an idea similar in size and purpose to Kerry's won Senate approval on a bipartisan voice vote -- a procedure reserved for non-controversial measures -- as an amendment to a larger bill sponsored by one Republican and one Democrat, said Kerry spokesman Chad Clanton.

The move came after the collapse of the Soviet Union, when there was wide recognition that intelligence spending needed to shift away from efforts to thwart the Cold War opponent and toward measures to combat terrorism, drug trafficking and weapons of mass destruction.

Kerry's bill would have stripped $90 billion from the overall budget to end programs he called "pointless, wasteful, antiquated or just plain silly," including $1.5 billion in cuts aimed at ending "bloat" in an intelligence budget that had become "essentially a slush fund for defense contractors," Clanton said.

"You bet, John Kerry voted against business as usual in our intelligence community," Clanton said.

Kerry aides also pointed to a 1996 report by a blue-ribbon panel that said it was "critical" to identify useful reductions to the intelligence budget.

Kerry, who has suggested that Bush is impeding a federal commission's investigation into the events leading up to the Sept. 11, 2001, terrorist attacks, played more than just defense on Monday.

"If the president of the United States can find time to go to a rodeo, he can spend more than one hour before the commission," Kerry said in Florida, referring to Bush's appearance at a rodeo Monday between Dallas and Houston fund-raisers. Both events added $3 million to his $160 million-plus campaign war chest.

The White House says Bush is cooperating with the investigation.

Bring On the Lawsuits

Meanwhile, while Kerry was campaigning in Palm Beach -- the Florida starting point of the 2000 recount debacle that ended up in the Supreme Court -- legal battles were already beginning in the 2004 campaign.

The Bush-Cheney campaign plans to file a complaint with the Federal Election Commission against a Democratic special interest called the Media Fund (search), which is run by former Clinton deputy chief of staff, Harold Ickes, and former Kerry campaign manager Jim Jordan.

The group plans to spend $4.5 million on anti-Bush TV ads in key battleground states. The Bush-Cheney campaign says the Media Fund is trying to influence the election and should have to register with the FEC as a regular political action committee and not be exempt from various new restrictions on special-interest group spending.

A Media Fund spokesman told Fox News that they are within the law because they do not directly call for the president's defeat and no corporate or union contributions are financing the ads.

Fox News' Carl Cameron, Kelly Wright and The Associated Press contributed to this report.