John Kerry (search) said Thursday that President Bush's musing about a national sales tax (search) is an insult to financially struggling voters and would amount to "one of the largest tax increases on the middle class in American history."

The Democratic presidential nominee, during a speech at California State University, Dominguez Hills, tried to reverse partisan stereotypes by portraying the Republican president as the tax raiser and himself as a tax cutter.

Kerry said if Bush wants to create a national sales tax without increasing the deficit, people will end up paying at least 26 percent more for purchases on top of state and local sales taxes.

"We know exactly who that's going to hurt," Kerry said. "That's going to hurt small business. It's going to hurt jobs. It's going to hit the pocketbooks of those who need and deserve tax relief most in America."

Bush has suggested that overhauling the tax code would be a second-term priority if he is re-elected. While campaigning in Florida (search) Tuesday, he said replacing the income tax with a federal sales tax is "an interesting idea that we ought to explore seriously."

Kerry seized on Bush's comments even as White House officials downplayed the idea and denied that any such plan is under consideration.

Kerry said Bush has failed to offer a plan for improving the economy in his second term. He said the president's tax cuts have resulted in a tax increase on the middle class because their state and local taxes have been increased to compensate for loss of revenue from the federal government. He said a national sales tax would only further burden the middle class.

"I call it one of the largest tax increases on the middle class in American history," Kerry said. "And this is coming from an administration that has offered almost no new ideas for our economy, and the few ideas that they have offered have only hurt middle class families. This new idea is no different."

Kerry repeatedly invoked the memory of better economic times under another Democratic president, Bill Clinton. He said Clinton's advisers were helping craft his economic plan and that he will be "a champion for the middle class" by cutting their taxes while lowering the deficit.

Kerry said he would offer tax breaks to help pay for health care premiums, child care and college tuition, paid for by repealing Bush's tax cuts for people earning more than $200,000 a year.

"They will go back to paying the same taxes they paid when Bill Clinton was president," Kerry said. "That was a time when every American got richer."

Bush campaign spokesman Steve Schmidt said Kerry cannot pay for his tax plan.

"John Kerry's numbers don't add up," Schmidt said. "He has spent his tax hike more times than anyone can keep track of."

Kerry was also fighting the Bush campaign's charge that Kerry has a long history of voting for higher taxes during his 19-year career in the Senate.