President Bush and Democratic challenger John Kerry face off in their first debate later Thursday at the University of Miami in the southern state of Florida.
The Republican and Democratic candidates will focus on foreign policy in this first of three debates for the presidential contenders.
Iraq is expected to be at the center of that discussion as President Bush says last year's U.S.-led invasion has made America safer from terrorist attack. Senator Kerry says President Bush misled the nation into war without a broad enough international coalition to share the costs.
In the debate, Republican officials say, President Bush will continue trying to portray Senator Kerry as an inconsistent, so-called "flip-flopper" on Iraq for voting to authorize the use of force but voting against some of the money to fund U.S. troops.
Senator Kerry says he supports the troops but wanted that money to come from scaling back the president's record tax cuts. Democratic officials say the senator will try to convince voters that President Bush has made the nation less safe by focusing on Iraq to the detriment of the fight against terrorism.
With 33 days to go before the vote, most public opinion polls show President Bush leading Senator Kerry by between three and five percentage points.