President Bush (search) sought to rally re-election support Saturday in the state that put him in the White House, taking on John Kerry (search) over the Democrat's budget proposals.

At the first official campaign rally of his re-election bid, Bush was making the case that the Massachusetts senator has not given an adequate explanation of how to pay for his spending plans, said a senior administration official, speaking on condition of anonymity.

During Bush's 20th visit to the state as president, Republicans were organizing a voter registration drive across central Florida.

Bush was last in Florida, which both parties regard as critical to the November elections, in February when he opened the Daytona 500 NASCAR (search) race.

Bush used his first negative ad against Kerry to contend that the presumptive Democratic nominee would raise taxes by $900 billion if president. The figure comes from estimated costs of the health care plan Kerry has proposed. Kerry has not yet said where the money would come from to pay for the new health benefits.

Kerry also has supported rolling back the portion of the Bush tax cuts that go to those that earn more than $200,000 a year, which most estimates agree would save about $250 billion over 10 years.

The argument that Kerry is promoting job-killing policies to raise taxes and discourage free trade is a staple of the Bush campaign.

Another is the accusation that Kerry flip-flops and his leadership on national security and other issues cannot be trusted.

In his address, Bush was expected to cite Kerry's vote against an $87 billion bill funding military and reconstruction efforts in Iraq and Afghanistan, the administration official said.

In explaining that vote, Kerry said this week, "I actually did vote for his $87 billion before I voted against it."

Kerry supported a failed amendment to the bill that would have paid for the Iraq and Afghanistan missions by repealing Bush tax cuts. His line was quickly incorporated into a Bush ad against Kerry now airing nationally.

Kerry supported Bush's Iraq war resolution and then campaigned against how the president has conducted the Iraq campaign. Kerry says he voted against the spending bill because he did not support the president's postwar plans.

On the eve of Bush's Florida appearance, the Kerry campaign said the president has left a trail of broken promises.

"President Bush's economic policies have failed Florida," said Rep. Kendrick Meek (search), Kerry's state campaign chairman. Bush's "corporate buddies have shipped 70,000 Floridian manufacturing jobs overseas and now it's time for Mr. Bush to get the pink slip."

Sen. Bob Graham (search), D-Fla., said that in the Orlando area, the jobless rate in January was 4.4 percent, compared with 2.5 percent with Bush's election, a loss of 40,000 jobs.

In 2000, Democrat Al Gore (search) contested Bush's narrow victory in Florida, arguing that some votes were not counted because of voting problems. Recounts conducted in some counties were stopped by the U.S. Supreme Court after 36 days, handing Bush a 537-vote victory in Florida that gave him enough electoral votes to win the presidency.