Updated

As final preparations were being made for the first vice presidential debate, President Bush (search) and John Kerry (search) continued on the campaign trail Monday.

Bush was in one of the most hotly contested states, Iowa, to sign his fourth tax cut (search) in four years. The White House held the signing ceremony Monday at a YMCA in Des Moines — a Democratic area of a state that Bush lost by a razor-thin margin in 2000.

Bush, who holds an "Ask President Bush" event in nearby Clive, Iowa, later Monday, hopes to win Iowa by appealing to conservative Democrats.

Kerry, Bush's Democratic challenger, follows Bush into Iowa this week, appearing Tuesday in Tipton to discuss issues that concern middle-class Americans. The Hawkeye State, one of six states decided by fewer than 10,000 votes in the 2000 election, has been a frequent destination of both campaigns.

On Monday, Kerry held a town hall meeting in Hampton, N.H., where talked about his commitment to restoring America's leadership in science by expanding embryonic stem-cell research (search). Kerry was to be joined by actor Michael J. Fox and several New Hampshire area residents who will speak personally about the importance of research in that field.

With a new campaign ad, Kerry criticized Bush's decision to limit federal funding for research on embryonic stem cell lines created after Aug. 9, 2001, a policy that critics say stifled research. Some religious and conservative organizations oppose the research because days-old embryos are destroyed in the process.

Kerry promises to earmark $100 million a year for the research and insist on strict ethical oversight.

"The hard truth is that when it comes to stem-cell research, our president is stifling science for ideology and playing politics with people who need cures," Kerry said in his remarks Monday.

"Right now, some of the most pioneering treatments could be right at our fingertips, but because of the stem-cell ban they remain beyond our reach."

Stem-cell research got national political attention this summer when President Reagan died after a long battle with Alzheimer's (search) disease. Reagan's wife Nancy and son Ron urged the administration to lift the funding restrictions. Kerry was among 58 senators who asked Bush to relax his policy.

Some supporters of the Bush policy argue that Alzheimer's patients won't be the first beneficiaries of increased use of embryonic stem cells and that not enough proof has even been shown that embryonic cells are better than adult stem cells in helping further study on currently incurable diseases.

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.

The population in the eastern half of the state, where most Iowans live, is split between Republicans and Democrats. The more rural western half is heavily conservative and Republican.

The tax-relief measure signed by Bush will affect about 94 million Americans. The bill keeps three middle-class tax breaks from expiring Jan. 1 and revives other tax incentives for businesses.

The tax relief equals about $131.4 billion in savings to taxpayers over the next decade. In addition to personal relief, Republicans added provisions to extend 23 tax breaks for businesses that were set to expire. The biggest item in this group, which totals $12.97 billion, is a tax credit to businesses for research and development.

Kerry backed the middle-class tax breaks, 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 increased revenue 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 by one dime."

"Now that the middle-class tax cuts that John Kerry supported so vigorously in the Iowa caucuses are being extended, the lines are clear: Bush wants more tax breaks for the wealthy, Kerry wants to cut taxes and health costs for middle-class families," said Kerry spokesman Phil Singer. "Kerry is proposing twice as much in new middle-class and job-creating tax cuts as Bush."

Jobs and taxes will be just two issues open for discussion during Tuesday's one and only vice presidential debate. Cheney and Edwards are facing off at Case Western Reserve University in Cleveland, Ohio. It will be moderated by Gwen Ifill of PBS.

The next presidential debate is scheduled for Friday at Washington University in St. Louis, Mo. It will be moderated by Charles Gibson of ABC News. This is the only debate with a town hall format where pre-selected audience members will ask questions directly of the candidates.

The final presidential debate on domestic policy is scheduled to take place at Arizona State University in Tempe, Ariz., on Oct. 13. Bob Schieffer of CBS News will be the moderator.

A couple of new polls show Kerry has closed the gap or even taken a slight edge over the president. The latest Gallup poll, released Sunday, shows Kerry and Bush tied at 49 percent each among likely voters with independent candidate Ralph Nader drawing 1 percent. The margin of error was plus or minus 4 percentage points. A poll taken by Gallup in the week before the Sept. 30 debate had Bush ahead of Kerry among likely voters 52 percent to 44 percent.

In state polls, a Quinnipiac poll of 723 likely Connecticut voters gave Kerry 50 percent support and Bush 44 percent. The survey, conducted Sept. 26-28, found that 2 percent support went to independent candidate Ralph Nader while another 4 percent were unsure.

A Detroit Free Press poll of 830 registered Michigan voters gave Kerry a 2-point lead over Bush with 48 percent support, giving the president 46 percent. Nader got 2 percent and 4 percent were unsure.

A Mason-Dixon poll of 625 likely voters in Virginia gave Bush 49 percent support over Kerry's 43 percent. The survey, taken Sept. 24-27, gave 1 percent support to Nader while 7 percent were unsure.

But in North Carolina, a Mason-Dixon poll conducted Sept. 26-28 found that Kerry had 43 percent support to Bush's 52 percent. Another 5 percent of the 625 likely voters surveyed were unsure.

The Associated Press contributed to this report.