This is so close to the accusation that Romney is making in the present election that it is incumbent on the mainstream media to ask whether Obama, only 12 years before being elected president, was a member of a political party that openly espoused those anti-business, redistributive, social democrat views. Yet even though there is now documentary evidence to prove that he did indeed join a leftist third party, there has been not the slightest whiff of interest so far in pursuing the story from ABC, CBS, CNN, the New York Times, the Washington Post and so on, and only one report on National Public Radio, which came to no definite conclusion. By contrast, try to imagine the furore from all those news organisations if documentary evidence had been discovered that proved that in 1996, when he was in his last year at Bain Capital, Mitt Romney had joined the Libertarian Party and signed a "candidate's contract" to espouse its views as Governor of Massachusetts, and had then released a statement describing the accusation as a "crackpot smear".  

When vice-presidential candidates are about to be appointed, a huge amount of vetting is undertaken. The presidential candidate's team trawls through their pasts to a highly inquisitorial degree. Past associations, tax records, ex-girlfriends, political friends of friends, all jobs and posts held going back to high school — everything is fair game as the candidate tries to find skeletons in his potential running-mate's closet before the media does. Yet the parties impose no such fine-tooth-combing through the presidential candidate's past, meaning that revelations such as Kurtz's can come out even four years into a presidency.

By the time you read this, Romney might have already chosen his vice-presidential running-mate, although the more traditional, cautious timing is to announce it at the late-August nominating convention, and Romney is nothing if not traditional and cautious. The front-runners are Senator Rob Portman of Ohio, Senator Marco Rubio of Florida, Governor Chris Christie of New Jersey and Governor Susana Martinez of New Mexico, with perhaps as many as five others also in contention. Since the choice of "veep" is the first important judgment call that the candidate has to make, it is analysed in immense detail as much for what it says about the candidate as about the veep.

Although Rubio is Hispanic, handsome, charismatic, "the crown prince of the Tea Party movement" and comes from the key battleground state of Florida, he is also very young (41), his parents were economic migrants rather than Castro exiles, and he has not so far broken his close ties with his allegedly corrupt friend Representative David Rivera of Florida's 25th Congressional District. Susana Martinez ticks very useful psephological boxes, being both Hispanic and a woman, but the choice might look opportunistic for that very reason. Americans are very harsh on candidates who choose veeps for their electoral interests rather than picking someone who would be well-qualified enough to be "a heartbeat away from the presidency". Punishing John McCain for choosing Sarah Palin was one of the reasons the Republicans lost in 2008, although no one is suggesting that Ms Martinez is not far better qualified to be president than was Mrs Palin. John Kerry's choice of John Edwards of North Carolina in 2004 was similarly more about shoring up the weak Democratic vote in the South than choosing the best man for the job, as the recent scandals over Edwards's private life and unorthodox campaign financing have subsequently shown.

The whole intellectual climate is changing in what are called "the veepstakes". No longer is it assumed that veeps can do that much to deliver even their home states for the candidate, and so the argument is made that a veep should underline and complement the candidate's own strengths, rather than attempt to fill in whatever is missing in terms of his geographical, racial or gender appeal. Since 1920 veeps have produced on average a net gain of only 2 per cent in their home states, although the numbers have been growing slightly since 1984. Sitting governors and senators tend to deliver higher gains than congressmen or people who have retired from state office, while veeps from smaller states — especially ones that rarely produce national candidates — tend to do better than those from bigger states, as the strong turnouts for Sarah Palin in Alaska and Joe Biden in Delaware showed in 2008.This effect subsides, however, once they've spent four years in Washington and are on the ticket for the second time.