President Bush (search) on Saturday questioned Sen. John Kerry's (search) "ability to lead our nation," raising the Democrat's year-old opposition to emergency funding for the Iraq war to paint his rival as too fickle to be trusted with America's safety.

Bush said it was simple: Kerry failed to support American troops in harm's way when he voted against an $87 billion for military and reconstruction efforts in Iraq and Afghanistan. Noting the vote was a year ago Sunday, Bush mocked Kerry for at first saying it would be irresponsible to oppose the measure, and then doing just that.

Bush, repeating a common campaign charge, said the change of heart was purely for political expedience, coming just as former Vermont Gov. Howard Dean (search) was gaining steam as the party's anti-war candidate.

"Senator Kerry apparently decided supporting the troops even while they were in harm's way was not as important as shoring up his own political position," said Bush, speaking in a 20,000-seat sports arena that appeared about half-full. His campaign bus drove into the darkened arena to deposit the president amid strobe lights and swirling smoke.

"At a time of great threat to our country, at a time of great challenge to the world, the commander in chief must stand on principle, not the shifting sands of political convenience," he said.

Kerry voted against the $87 billion funding bill, which passed the Senate. Before the final vote, however, Kerry voted for a resolution that would have required the funding to be paid for by repealing Bush's tax cuts. That measure that did not pass, leading to Kerry's 'no' vote on the final bill.

Kerry has struggled to explain his stance ever since — even though Bush himself threatened to veto the bill because he also didn't like some elements of it, particularly a later-removed provision that would have made some of the money loans that Iraq would have to repay.

In the homestretch of a newly tightened race, Bush was campaigning by bus and plane throughout Florida, the state that decided the 2000 election. He was appearing at rallies in West Palm Beach and at the Daytona International Speedway, each time introduced by his brother, Florida Gov. Jeb Bush. All three stops were in counties that Democrat Al Gore won four years ago.

Florida is among the handful of states both sides consider still in play, and the one offering the largest electoral prize. Kerry's running mate, Sen. John Edwards, was campaigning nearby in Miami on Saturday.

Florida's lashing by four major hurricanes has complicated campaigning and polling. Some polls show Bush ahead and others indicate a close race.

A poll released Saturday showed Bush and Kerry neck and neck, each getting 48 percent from a sample of 655 likely voters surveyed Oct. 4-10. Bush had a 2-1 lead among Hispanics, a critical group of Florida voters. The survey by The Washington Post, Univision and the Tomas Rivera Policy Institute had a margin of error of 4 percentage points.

Also Saturday, Bush used his weekly radio address as a campaign tool, mentioning his unnamed "opponent" five times to plead the case that he, not Kerry, has a better slate of ideas on the economy, taxes, education and health care.

While in Florida, Bush appealed to the state's large Jewish population by noting he had earlier in the day signed a bill requiring the State Department to document attacks on Jews around the world. Earlier this week, the State Department said it opposed the measure as unnecessary because of work the Bush administration already does to combat anti-Semitism.

The president has for months sought to portray Kerry as a potentially dangerous commander in chief, arguing the Democrat shifts positions with the political winds. As proof, Bush often takes Kerry's statements on Iraq out of context, contrasting that image with one of Bush as a president who is steady in the face of a treacherous world.

The Kerry campaign dismissed the criticism.

"John Kerry, meanwhile, will spend Saturday in Ohio talking about a key issue facing Americans today: the flu and the Bush administration's failure to deal with the vaccine shortage," Kerry spokesman Phil Singer said. "After spending an entire campaign unsuccessfully using the $87 billion as a political cudgel, the Bush campaign thinks it will suddenly resonate."

The Kerry campaign noted that Bush's attack ignores the president's handling of Iraq, where the situation has worsened, where nearly 1,100 U.S. soldiers have died, and in which the central rationale for invasion Iraq — Saddam Hussein's alleged weapons of mass destruction — has been debunked.

"So if George Bush really wants to take a look back over the last year, let's do that," Singer said. "Happy anniversary, Mr. President."