CLIVE, United States (AFP) - US President George W. Bush and Democratic rival John Kerry battled over science, taxes and Iraq, as the spotlight of their newly tight race shifted to their running mates' only televised debate.
After signing legislation extending popular tax cuts, Bush said in the key up-for-grabs state of Iowa that Kerry would raise taxes on the US middle class and warned that his foreign policy would be "dangerous for world peace."
Wooing voters in the battleground state of New Hampshire, Kerry accused Bush of choosing to "sacrifice science for extreme right-wing ideology" by restricting the use of government funds for stem-cell research.
The two candidates, next scheduled to face off in person on Friday, sized up polls showing Kerry clawing even with the Republican on the strength of his showing Thursday in their first of three televised debates.
A USA Today/CNN/Gallup poll had the two men tied at 49 percent among likely voters, wiping out an eight-point Bush advantage. A Newsweek magazine survey gave Kerry a three-point edge among registered voters.
Bush, who lost Iowa by a hair in 2000, has a razor-thin edge there. Kerry and the president look tied in New Hampshire, which narrowly went to Bush in 2000.
Bush's tepid performance in the debate added importance to Tuesday's encounter between Vice President Dick Cheney and his Democratic counterpart, Senator John Edwards, in the midwestern city of Cleveland.
Commentators said Cheney would seek to repair the damage from Kerry's relentless attacks on the Iraq war and renew the focus on Bush's leadership after the September 11, 2001 terrorist strikes.
Edwards was likely to use his skills as a trial lawyer to skewer Cheney as the architect of the administration's security policies, which led to windfall reconstruction contracts for his a company he formerly ran, Halliburton.
With the November 2 election closing fast, the president and the challenger were to square off Friday in the second of their three debates in the midwestern city of St. Louis, Missouri.
The Kerry campaign kept up the pressure Monday, publishing a list of more than 180 former US ambassadors endorsing the Democrat, out of concern over the administration's foreign policy.
Meanwhile, Bush redoubled his efforts to discredit Kerry as a potential commander in chief, pointing to the senator's vote against the 1991 Gulf War to oust Saddam Hussein's forces from Kuwait.
"The policies of my opponent are dangerous for world peace. If they were implemented they would make this world not more peaceful, but more dangerous," Bush told cheering supporters in Clive, Iowa.
Kerry was joined in the eastern city of Hampton, New Hampshire by actor Michael J. Fox, who suffers from Parkinson's disease, as he blasted Bush's decision to limit publicly funded research using stem cells from human embryos.
He said such studies could help find cures for diseases such as Parkinson's, Alzheimer's and diabetes. "This president is making the wrong choice to sacrifice science for extreme right-wing ideology," Kerry said.
Kerry, who reissued a list of 48 Nobel Prize-winning scientists who endorsed his position, said he would lift "ideologically driven" restrictions on stem cell research and fund it with at least 100 million dollars a year.
Under pressure from religious groups, who see the practice as akin to abortion, Bush moved in August 2001 to bar the use of public funds for research using stem cells from human embryos after that date.
But his campaign reacted harshly Monday to suggestions he had instituted an outright ban. "These characterizations are inaccurate or incomplete, and misinform the public on the reality of the policy," a statement said.
And Bush himself fired back on the medical front, likening Kerry's proposals to the failed attempt to overhaul health care, which was spearheaded by then first lady Hillary Clinton ten years ago.
"My opponent believes that the federal government ought to be making the decisions," Bush told cheering supporters the Iowa capital of Des Moines. "He's got a system that's creeping toward 'Hillarycare.'"
Bush also signed legislation extending tax relief for married couples, a tax credit for children and expanding a 10 percent tax rate to include more low-income families. He warned against Kerry's pledge to roll back taxes on the wealthiest Americans.
"He says, oh, I'm just going to tax the rich. Well, the rich hire lawyers and accountants for a reason -- that's to stick you with the tab," said Bush, who like Kerry is a millionaire.
Bush's campaign unleashed another television advertisement against Kerry, who has condemned the administration's 10-year, trillion-dollar tax cuts as overwhelmingly benefiting the wealthiest and major US firms.
The commercial accuses Kerry and other Democratic lawmakers of voting 350 times for higher taxes, including increased levies on gasoline and Social Security benefits.
The Kerry campaign countered by accusing the administration of doing nothing to reduce the country's dependence on Middle East oil, as costs hover near 50 dollars a barrel.