US: Usually vice-presidential debates don't matter that much, but the encounter between Vice-President Dick Cheney and Senator John Edwards in Cleveland this evening is expected to be a highly-charged affair that could impact on the presidential election.
It pits a powerful, hawkish vice-president against a youthful upstart out to undermine his credibility; a balding, taciturn westerner against a southern populist with great hair; a shrewd CEO against a trial lawyer who has battled big corporations.
The format at Case Western Reserve University on the outskirts of Cleveland - both men seated at a table - is expected to benefit Cheney who is at his best in a boardroom setting, whereas Edwards excels when working a crowd, or a jury, when on his feet.
The stakes could not be higher, with the latest Gallup poll showing President Bush and Democrat Mr John Kerry in a dead heat among likely voters with 28 days to polling on November 2nd.
Before the first presidential debate in Miami on Thursday last Mr Bush was eight points ahead in the Gallup poll, but Mr Kerry gained five points with his strong performance and Mr Bush lost three points, making the race dead even at 47 per cent each among likely voters.
The president's poor performance against the Democratic challenger places a burden on Mr Cheney to create new doubts about a Kerry presidency on the issue of national security while redefining his boss as a principled leader.
The lone vice-presidential debate comes at the height of the nastiest, most personal US presidential campaigns in memory, during which Mr Cheney has taken on with relish the role of denigrating the Democratic duo as flip-flopping, tax-raising liberals.
Four years ago the vice-presidential debate between Dick Cheney and Democratic candidate Al Gore's running mate, Senator Joe Lieberman, was a gentlemanly affair, with the former Halliburton CEO deferring to his opponent throughout as "Joe".
In that debate, which began with Lieberman saying "I'm going to be positive" and his opponent replying that he was "glad to be here with Joe", Cheney promised that Mr Bush would "come to grips" with the Arab-Israeli conflict.
He also stated when the issue of Iraq's weapons of mass destruction came up, "We don't know for sure about what might be happening inside Iraq."
Mr Edwards is likely to throw such comments back at the Vice-President tonight, as well as Mr Cheney's warning in 1992 against getting bogged down in Iraq, which the North Carolina senator has already used to charge his opponent with inconsistency.
Mr Cheney is one of the main architects of the invasion of Iraq, and he justified military action by stating as a fact that Saddam Hussein had reconstituted its nuclear weapons programme and that he had links to al-Qaeda, both of which claims have since been discredited.
Mr Edwards' goal will be to depict Mr Cheney as a sinister figure, whose former company won huge no-bid contracts in Iraq, but observers said he runs the risk of seeming hysterical against an elder statesman who is hard to rile and can use a dry wit to good effect.
White House spokesman Mr Scott McClellan said yesterday that Mr Cheney will focus on depicting Senator Kerry as "someone who is constantly shifting his positions when it suits him politically, and someone who has a fundamental misunderstanding of the war on terrorism (with) a pre-9/11 mind set."
Yesterday Mr Kerry came to Ohio to open a new front against the Bush administration, accusing him of sacrificing hopes for disease cures offered by stem cell research to "extreme right-wing ideology."
Appearing with actor Michael J. Fox, who has Parkinson's Disease, the Democratic candidate promised to fund more embryonic stem cell research with federal money if elected.
The Kerry-Edwards campaign issued a new campaign ad says it's time to "lift the political barriers" blocking the exploration of stem cell therapies, a move which polls show would have the support of a majority of the American public.
Mr Bush has banned federal funding for research on embryonic stem cell lines created after mid-2001 after religious groups objected to the use of days-old embryos in the process.
The Massachusetts senator gets some of his biggest cheers at campaign rallies when he promises to fund more stem cell research, one aspect of a pledge to increase federal support of science.
Stem cell research got national political attention this summer when President Reagan died after a long battle with Alzheimer's disease and his wife and son Ron urged the administration to lift the funding restrictions.
Kerry was among 58 senators who asked Bush to relax his policy.