George, the elder brother, was lucky (or, some say, well-connected). He was given a coveted place in the Texan Air National Guard (equivalent to the British Territorials). He spent every weekend for six years as a part-time fighter- pilot operating on the US-Mexican border.
John, the younger brother, was a more sensitive type who spent his college days agonising about the morality of the war. He discussed with his Congressman father, an enthusiastic supporter of the conflict, whether he should become a conscientious objector. But John was also lucky. By the time his student draft deferment ended, the war was waning. He was never called up.
There is nothing remarkable about the stories of the brothers, whose full names are George W Bush Jr and John E (Jeb) Bush, the elder sons of the President. Of the millions of Americans eligible for the Vietnam draft from 1964 to 1973, less than 8 per cent - one in 12 - crossed the Pacific.
Unsurprisingly, the stories of the Bush sons recall those of two other young men in the late Sixties: Danny Quayle in Indiana (who was smuggled by his hawkish family into the National Guard), and Billy Clinton in Arkansas (who played the muddled student deferment rules, with family help, until in 1970 the draft began to wind down).
Why, then, is Mr Clinton's draft record re-emerging as the one issue most likely to extend the presidential Siberia of the Democratic Party? There are two answers, messily intertwined. First, Vietnam itself.
The Vietnam syndrome was listed by George Bush as a casualty of the Gulf war. But this was silly. The memory of the Vietnam war remains, to many Americans, a minefield of moral equivocation and political hypocrisy. It is one of the great fault lines in American society and politics, jointly responsible with the other great fault line - race - for destroying the Democratic coalition of Roosevelt, Truman and Kennedy. The US lost the Vietnam war, and frequently acted discreditably in doing so. But the myth remains, on the right-hand side of American politics and among many Vietnam veterans, that the war was lost in the US, not Vietnam.
Mr Clinton's second problem is Mr Clinton. He has skidded around the truth of his two-decade manoeuvring to avoid the draft, and has tripped up on at least two occasions. While saying he has nothing to be ashamed of, he has given the impression that he has something to hide. In part, Republican politicians are correct in saying the issue is not Vietnam, but Mr Clinton's honesty. They also hope to exploit Vietnam resentments to replay the flag and security themes that scuppered the Democrats in the Seventies and Eighties.
To call Mr Clinton a draft- dodger is patently unfair. In tax collector's terms, he avoided the draft, but did not evade it. He played the system for all it was worth. But so did millions of others. The deferment rules were constructed by Congress, including then Congressman George Bush, in such a way that the better educated you were, and the better off and better connected, the better chance you had of avoiding the fighting.
This was a kind of Darwinism: smarter, better educated people escaped the draft; poorer, less educated people went to Vietnam; and 57,000 to their deaths. Unsurprisingly, this remains a potent political issue with blue- collar white males, of just the kind who voted in droves for the Republicans in the Seventies and Eighties. Mr Clinton never made any bones about the fact that he opposed the Vietnam war. In theory, this should set him on morally higher ground than those who supported the war, as long as others fought it. Mr Clinton can point to a whole aviary of chicken-hawks: Republicans of his own generation who championed US involvement in Vietnam, but who did not care to serve there.
Here are a few case histories: George W Bush, now 46, entered the Texan Air National Guard - carrying an automatic draft exemption - after graduating from Yale University in 1968. He served as a weekend fighter pilot. Retired Major General Ross Ayers, commanding officer of the Texan National Guard at this time, denied that strings were pulled to circumvent waiting lists. But he said he had no illusions that the sudden crush to get into the Guard was not motivated by the desire to avoid the draft.
A Texan lawyer, who served in the Air National Guard with George Bush Jr, said: 'You could rationalise it in many ways: that you were serving your nation better by preserving your possibility of becoming a doctor or a laywer or whatever. But, frankly, we all knew that it was a way of being on the right side of the law and avoiding the possibility of being killed in the jungle.'
Jeb Bush, now 39, is a rather different case. Barbara Bush, in one of her many moments of apolitical candour, told a reporter in 1984 that Jeb had considered seeking formal status as a 'conscientious objector' to the Vietnam draft. By the time his college deferment ended, the draft was virtually over and Jeb never had to make a choice.
Dan Quayle, 45, accused Mr Clinton at the Republican convention of having a 'credibility problem' over Vietnam, and demanded that he 'come clean'. This is rich coming from a man who made a career as a military hawk and Red-baiter, but who spent the Vietnam years in the journalistic unit of Indiana's National Guard, chronicling the doings of his fellow guardsmen.
Pat Buchanan, 55, classified medically as 4F because of rheumatoid arthritis - but later an energetic jogger - served in the White House trenches in the later stages of the Vietnam war, making up alliterative attacks on liberals (such as 'nattering nabobs of negativism' for Vice-President Spiro Agnew). He says he contributed to the war effort by polishing Richard Nixon's image.
The Defence Secretary Dick Cheney, 51, got four student deferments - before the rules were tightened to exclude graduate studies - and then a fifth deferment as a father.
The danger of the draft issue to Mr Clinton is this: the Bush campaign can convert it into the same kind of slow puncture that the Willie Horton prison parole issue became for Michael Dukakis in 1988. This is the Republican way of campaigning: not to explode the opposition, but to use constant repetition, exaggeration and distortion of one or a series of issues to drain the opponent's credibility. Mr Clinton's prevarication on his draft record has created just the kind of opening Republicans needed.
A Clinton campaign pollster said late last week that there was no sign, so far, that the draft issue had challenged the sickly US economy as the '300lb gorilla issue' of the 1992 campaign. The Clinton camp was relieved last Wednesday when Mr Bush foolishly echoed his 'no new taxes' pledge of 1988, changing the subject from 'Can you trust Clinton?' to 'Can you trust Bush?'
But Clinton campaign officials concede that the Vietnam draft saga is the one issue they fear most. 'It's the one thing that makes the candidate look defensive,' one senior adviser said. 'It's the one thing that makes him look tired and rattled.'