Republican Vice President Dick Cheney and his rival Senator John Edwards are preparing for their only debate of the U.S. presidential campaign later Tuesday, an event expected to focus evenly on domestic and foreign policy issues.

The 90-minute televised debate in Cleveland, Ohio, comes as polls indicate the race is tightening between President Bush and Democratic nominee John Kerry.

Iraq is expected to play a prominent role in the debate, as is the economy and the war on terror.

Republican strategists say they expect Mr. Cheney, a political veteran, to offer a strong defense of the Iraq war and the Bush administration's foreign policy.

Democrats say Mr. Edwards will use his experience as a trial lawyer to press Mr. Cheney on his Iraq and energy policies, including his ties to Halliburton, a leading military contractor in Iraq.