The stakes were high for both candidates as polls after the two previous debates suggested the candidates were in a dead heat in the race for the White House.

The 90-minute debate in Tempe, Arizona, is the only one devoted to domestic issues such as jobs, health care and Social Security. The Iraq war and terrorism, however, are also expected to be brought up since the two issues have dominated the campaign.

Bush is expected to defend his tax cuts and his performance on economy. He has touted on his campaign trails that his tax cuts have benefited small business and added 1.9 million jobs in the last 13 months.

The Republican president would also focus on Kerry's Senate record and label the Massachusetts senator a liberal who would turn health care to government control and raise taxes to fund his plans for domestic programs.

"To pay for all the big spending programs he's outlined during his campaign, he's going to have to raise your taxes," Bush told supporters in Colorado Tuesday. "Raising taxes would be the wrong prescription for economic growth."

Kerry has promised to raise taxes only on those making more than 200,000 dollars a year and to give tax credit to middle class.His campaign said the Bush camp has distorted Kerry's health care plan by using misleading numbers.

The Democratic senator, who has closed up his pre-debate gap with Bush, is expected to lash out at Bush over job losses, rising gas prices and deteriorating budget deficits. Polls show Kerry has an edge on many of those domestic issues.

He is expected to highlight the fact that Bush is the first president in more than 70 years who has seen net job losses on his watch. The senator said in his first two debates that more than 1.6 million jobs have lost during the four years of Bush's office.

The senator will fight against Bush's effort to label him a "liberal" and is expected to repeat his promise not to raise taxes for anyone who earns less than 200,000 dollars a year.

He will detail a health care plan which he says would reduce the cost and still give the choice to the people, not the government.

In the hours before the debate, Bush won an expected endorsement from the National Rifle Association, a powerful group lobbying against any type of gun control. The association plans to spend about 20 million dollars to campaign on behalf of Bush.

Kerry criticized Treasury Secretary John Snow's comments that it was "a myth" that there had been economic failures on Bush's watch, saying the comments was an "outrageous slap in the face to America's middle class." The comments showed that the Bush camp was trying to "spin its way out of the problems facing working America," he said.