Besides, the second avenue of attack is that Mr Kerry has been a little too political himself, seldom showing the same mettle in internal Democratic politics that he did in the jungles of Vietnam.

ECONOMIST: How would the White House attack John Forbes Kerry?

But when Senator Obama tells crowds this is our moment, he means a new generation of Americans who do not treat politics like an oldie station, replaying every conflict as Vietnam, every scandal as Watergate and every issue as black and white.

NPR: The Changing Complexion of American Politics

It helps that these are the two candidates with the most impressive histories outside politics Mr Bradley as a basketball Hall-of-Famer, Mr McCain as a Vietnam war hero. (In contrast, Al Gore and most others are career politicians or pundits, George W. Bush being a partial exception.) But there is more to their appeal.

ECONOMIST: The underdogs start snapping

Might the waves of returning exiles who have got used to living in democracies also help transform Vietnam's politics?

ECONOMIST: Former refugees bring back skills and money