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President Bush signed his fourth tax cut in four years on Monday, extending three tax breaks popular with middle-class voters and reviving other tax incentives for businesses.

Bush held the bill signing ceremony at a YMCA in Iowa, one of the most contested states in this year's presidential election with Democrat John Kerry (search) and a state Bush lost by a razor-thin margin in 2000.

An estimated 94 millio which keeps three middle-class tax breaks from expiring Jan. 1 and renews others for businesses. The tax cut also will swell the deficit, which is at a record high.

"The law I sign this morning comes at just the right time for America," Bush said.

The $145.9 billion tax package that Congress passed last month will:

— Keep the per-child tax credit at $1,000 for five years.

— Continue to allow more of taxpayers' income to be taxed at 10 percent, the lowest rate, for six years.

— Retain for four years a provision giving married couples relief from the so-called marriage penalty.

The individual taxpayer relief is estimated to cost $131.4 billion in government revenue over the next decade. In addition, Republicans added provisions to extend 23 tax breaks for businesses that were set to expire. The biggest item in this group, which costs $12.97 billion, is a tax credit to businesses for research and development.

Kerry, who appears Tuesday in Tipton, Iowa, to discuss issues concerning middle-class Americans, backed the tax breaks in the Senate, saying they helped families being squeezed by a weak economy, falling incomes and rising health costs. But he has proposed rolling back the tax cuts for families making more than $200,000 and using the savings to make health care and education more affordable.

The Massachusetts senator also has proposed new tax cuts to help middle-class families — relief he says won't increase the deficit.

"There's a fundamental difference between George Bush and John Kerry on taxes," said Kerry spokesman Phil Singer. "George Bush wants more tax breaks for his special interest friends, and John Kerry wants to cut taxes and health costs for working families."

Bush said the bill he signed Monday, approved last week by Congress, "will extend vital tax relief for millions of American families and add momentum to our growing economy."

"Unless we acted, a family of four earning $40,000 would have seen their federal income taxes rise by more than $900," Bush said. "That would have been a burden for hardworking families across America. And it would have been a setback for our economy."

Iowa, one of six states decided by fewer than 10,000 votes in the 2000 election, has been a frequent destination for both campaigns.

Monday was Bush's 17th presidential trip to Iowa. Kerry has traveled there seven times. He also got a lot of exposure in the state during the nominating caucuses in January when he and running mate John Edwards (search), then a rival, rode late-breaking momentum to a one-two finish that put them on track to challenge Bush and Vice President Dick Cheney (search).

Polls show Bush with a slim lead over Kerry in Iowa, which offers seven electoral votes to the winner on Nov. 2.

Bush, who holds an "Ask President Bush" event in nearby Clive, Iowa, later Monday, hopes to win Iowa by appealing to conservative Democrats, particularly Roman Catholic voters who tend to side with the GOP on abortion, gay marriage and other social issues.

Kerry, assisted by Democratic Sen. Tom Harkin and Democratic Gov. Tom Vilsack, is hoping the state's economy and the Iraq war will keep Iowa in their party's win column.