Cue the violins, segue into the "Star Spangled Banner" and stand to attention. In good time for next year's US presidential election, patriotism is back. And so, inevitably, is Vietnam: the war that divides and defines a generation.
Mr McCain, who is now George W Bush's closest challenger for the Republican nomination, had not set out to trade on his war record. When he returned from Vietnam 26 years ago, and again when he entered politics eight years later, he said he wanted to put Vietnam behind him. His causes as a legislator have been the reform of political funding, curbing "big tobacco" and maintaining the country's defences.
Yet his first campaign advertisement capitalises shamelessly on his courage in war. It opens with him as a keen young Navy pilot, preparing for a combat mission over Vietnam. It ends with him as a senator, preaching the benefits of clean government.
In between, he is an injured prisoner of war, wincing from pain; a returning hero, hobbling down the aircraft steps; and a baby-hugging populist, touting for votes - a warrior-politician in the classic American mode.
Mr McCain's candidacy, and his steady rise in the poll rankings, have pushed Vietnam into the spotlight and, with it, the candidates' war records. But Vietnam would have been an undercurrent even if Mr McCain were not running. The four leading contenders are all of an age to have served and, with the divisions opened up by that war still not healed, their conduct then may have a bearing on their prospects now.
Together, they make up a portrait of a generation. When Uncle Sam called, two served in Vietnam and two did not. One Republican and one Democrat enlisted for active service; one Republican and one Democrat found alternatives.
Of the two who went to Vietnam, Mr McCain, the son and grandson of admirals, was a career officer who volunteered for combat. His choice was, in one sense, the easiest.
By contrast, Al Gore, the son of an anti-war senator, was in turmoil. His father, senator for Tennessee, faced a traditional, pro-war electorate and stood to be booted out of office for his views.
Young Al convinced himself that he could salve his conscience and save his father if he did his patriotic duty. He enlisted, out of the glare of publicity, and went to Vietnam as an army reporter, describing the heroism and carnage he witnessed.
With George W Bush and Bill Bradley, the facts - and the motives - are murkier.
Mr Bush, like Mr Gore the son of a political father with honour to lose, enlisted in the Texas Air National Guard days before graduating from Yale.
Some question whether he was admitted on his merits, as he, the guard and his family insist, or whether he benefited from some paternal string- pulling to save him from the draft. The National Guard was an escape route for the well-connected and its very mention raises the hackles of those without such connections.
Bill Bradley's service record also has a whiff of privilege. A noted basketball player with an Olympic gold medal and a professional contract, he enlisted in the Air Force Reserve just as his final draft deferment expired. The Reserve, like the National Guard, was a known escape route, though a slightly less secure one, as Reserve units - unlike the National Guard - might be dispatched to Vietnam. It was not likely, but it was possible.
Like Mr Bush and Mr Gore, Mr Bradley appears to have engaged in much heart-searching before making his choice. Even so, Mr Bradley seems to have enjoyed more privileges than most, being allowed to play for his team, the New York Knicks, and still gaining laudatory reports from his military superiors.
Nearly 30 years on it is no longer the nature of the candidate's service or his view of the war that matters to voters. That issue was clumsily fought, but still won, by Bill Clinton eight years ago. Now, the question is how the candidate dealt with the draft: his response is seen as a touchstone for his reliability, veracity and, yes, honour - old-fashioned virtues that the voters want back.
This is why Mr Gore's war service as a reporter, if it is seen as a "soft" option, may be less of an electoral advantage than it was. This is why Mr Bush and Mr Bradley may find themselves confronting searching questions about how they came to serve where they did.
And it is why Mr McCain - the only real warrior among them - may be hailed as a conciliator: someone who just might banish the spectre of Vietnam from American politics for good.