U.S. Vice President Dick Cheney and Senator John Edwards, the vice presidential nominee of the centre-left Democratic Party, will square off Tuesday night in their only scheduled debate. The 90-minute debate at Case Western Reserve University in Cleveland, the largest city in the battleground state of Ohio, will see the two major-party running mates sitting at a table with moderator Gwen Ifill, a public television news anchor. Democrats and Republicans alike figure Edwards will be a tough opponent for Cheney, citing his years in the courtroom as a trial attorney. Republicans hope the a strong showing by Cheney will restore President George W. Bush's lead in the polls. The live audience in the arena will be 240 invited guests, plus a small number of journalists at the back of the room. The event begins at 9 p.m. Tuesday (0100 Wednesday GMT). A nationwide television audience of at least 25 million people was expected to watch. The vice presidential debate follows last week's foreign policy debate between Bush, the nominee with Cheney of the centre-right Republican Party, and challenger Senator John Kerry, who chose Edwards as his running mate. --MORE 2252 Local Time 1952 GMT