'If he can make Hillary look bad, he's gonna make McCain look pretty bad,' says Mr Devin, who has been driving in the capital for the last 38 years.

Senator Hillary Clinton is scarcely mentioned in Mr Obama's speeches now, after her game-changing defeat in North Carolina and a narrower-than-expected win in Indiana in last week's primaries.

On Saturday, Mr Obama overtook her by three votes to land 274 superdelegates in his column. In the overall count, he now leads her by 1,865 to 1,697, says RealClearPolitics website. As many as 2,025 votes are needed to win.

He has declared he may claim the nomination on May 20 and has begun engaging Mr McCain, the presumptive Republican nominee.

While Mr McCain took the weekend off, Mr Obama defined the imminent battle at a stump stop in Oregon which holds a primary in two weeks.

'Rather than an abstract set of questions about, 'Is he too liberal, is he too conservative, how do voters handle an African American, etc...', I think this is going to be a very concrete contest around very specific plans for how we improve the lives of Americans,' Mr Obama said.

'I think it is going to have to do with who has a plan to provide relief to people when it comes to their gas prices, who has a real plan to make sure that everybody has health insurance, who's got a real plan to deal with college affordability.'

After eight years of Republican rule, the ground is ripe for a Democrat to win the White House but analysts expect a close contest. The latest Gallup poll conducted last week shows Mr Obama with a one point lead over Mr McCain.

What adds to the unpredictability of the contest is that on issues that are of topmost concern to the voter, including the economy, neither candidate has a clear lead.

Further, both have trouble with their party's core supporters. Mr McCain, 71, seen as a maverick and a moderate, cannot carry the conservative and ideological Republicans, who are put off by his soft stance on issues like abortion and immigration.

Mr Obama, 46, has that peculiar problem too. As tomorrow's primary in West Virginia will underscore once again, he has been nowhere as successful with blue-collar white Americans - the traditional Democrats - as he has been with African Americans and upper- and middle-class white voters.

Supposedly, it will be a gentlemanly battle - both have sworn to keep away from politics as usual - with principled debates on issues.

'They may keep above the fray themselves but it's not their choice alone,' says Mr John Fortier of the American Enterprise Institute, an independent think-tank.

'Many independent groups, not allied to the parties or funded by them, will run tough attack ads,' Mr Fortier added.

Mr Obama's 'friendly relations' to a 1960s rehabilitated, but unrepentant, terrorist William Ayers, and to the controversial pastor Jeremiah Wright is fodder for the Republican attack machine.

The surrogates are not constrained either.

On Friday, an Obama supporter invoked Mr McCain's role in the savings and loan scandal of the late 1980s. He was one of five senators disciplined for improperly trying to influence federal regulators. It was, Mr McCain has said, 'the worst mistake of my life.' Mr Obama said it was fair game to dredge up Mr McCain's record.

The Republican campaign has been sniping too. Mr McCain has frequently described Mr Obama as 'Hamas' favourite' after the Palestinian terrorist group has said it hoped Mr Obama would win.

When Mr Obama said he found those comments offensive and that his rival had 'lost his bearings', the McCain camp retaliated by depicting Mr Obama as an ageist.

With just six months to go till D-day, what is turning out to the shortest general election campaign may well turn out to be the bloodiest.

bhagya@sph.com.sg