It is a regrettable feature of modern American life that the lofty tenor of political debate is increasingly drowned out by the low drone of scurrility.

In the early 1990s, the success of Clarence Thomas’s nomination to the Supreme Court hinged for a while on whether or not he had made remarks about pubic hairs on a Coke can to a young female assistant. Despite efforts to build his bridge to the 21st century, Bill Clinton never managed to lift his presidency above the flotsam and jetsam of semen-stained dresses.

This week we’ve been hearing far more than we need to know about how men behave in public lavatories. For this latest downturn in the public discourse we have to thank Larry Craig. Mr Craig is a hitherto not especially distinguished Republican senator from Idaho. He built a reputation as a staunch paragon of the virtues of the pre-Brokeback Mountain West. He is a strong gun advocate, a supporter of small government and a firm believer in family values.

After this week, he is destined to be remembered for having what he describes as an unusually “wide stance” when seated at the lavatory. That, at least, was how he attempted to explain what happened in June in a men’s room at the Minneapolis airport, news of which became public just this week.

According to an undercover detective investigating reports of lewd behaviour in said lavatory, on the afternoon in question, Mr Craig entered the bathroom stall next to his, and having taken his seat, began tapping his foot on the floor. The detective recognised this as a sign used by men soliciting sex and responded by lifting his own foot up and down. Then Mr Craig allowed his right foot to touch the detective’s left foot underneath the partition; in the semiotics of lavatory cruising, this was the clincher.

Not so, said Mr Craig, following his arrest. Their feet touched merely because the senator had an unusually “wide stance” when seated to answer the intestinal call. As a defence this might just have worked. If you think about it, the detective next door must also have had a similarly wide stance. We’ve all heard of the long arm of the law, after all; perhaps this was merely an example of similar anatomical deformity. With a bit of bluster Mr Craig might have pulled it off.

But the senator’s explanation was fatally undermined by his decision to plead guilty to disorderly conduct, desperate to keep the incident from becoming public, and the revelation that his local newspaper had been investigating allegations of similar behaviour over a 25-year period.

The incident has elicited predictable expressions of disgust and ribaldry. Mr Craig’s Republican colleagues have supplied most of the former with calls for his resignation. Democrats, observing that ancient political rule never to interfere when your opponent is imploding, have remained silent. Everybody else has supplied the ribaldry.

But beyond the comic fodder, and the little human tragedy for Mr Craig and his family, there is a larger consequence of the sordid incident. It is the latest, but perhaps most damaging, in a spate of revelations of sexual misconduct by straitlaced Republicans. A year ago Mark Foley, a congressman from Florida, resigned after he was caught exchanging explicit sexual messages with young male congressional assistants. Earlier this year David Vitter, a Louisiana senator, acknowledged that he had been a client of a notorious Washington madam.

The ramifications of this are threefold. First, there is a danger that the Republicans are just one libidinous old man away from becoming a national joke. It is rather reminiscent of the Tories in the 1990s, when you couldn’t open a newspaper without reading about some Tory minister with his pants down. The lasting damage of public ridicule cannot be overstated.

The second consequence is deepening disgust at politicians who have been in power so long that they believe they are no longer answerable to the normal dictates of decency and the law. In some ways the most revealing aspect of the Minneapolis airport episode was that Mr Craig whipped out his business card with its embossed seal of the United States Senate and said to the arresting officer: “What do you think of that?” When you have been in power for so long you tend to act like that. Though Democrats now control Congress, this popular disgust at the excesses of the powerful still has the potential to hurt Republicans, who have run this country, far more.

But the biggest implication may be that, through their own hypocrisy, Republicans have finally drawn a line under the era they dominated, in which personal morality was seen as a legitimate issue for public policy.

Mr Craig’s wide stance may straddle the high water mark of the moralistic preachiness that has come to characterise too much of the political debate in the last 20 years. Republicans have won many votes on the claim that they are not better rulers but better human beings than their opponents. Not any more.

Conservatives claim double standards here: when Democrats get up to monkey business, they seem to get away with it. This is true, but irrelevant. But lefties everywhere are generally deemed by their opponents to be louche, permissive roués, committed to the degradation of society through licentious behaviour. So when we discover, as we frequently do, that they are in fact louche, permissive roués, who commit licentious acts that degrade society, the only appropriate response is a shrug of the shoulders.

But when those misbehaving have established their political appeal at least in part on their superior values and faith, their proximity to God and their knowledge of His intentions, it matters more. You can’t adopt a firm stance on public morals in the hope of soliciting votes, while adopting a wide stance in public lavatories in the hope of soliciting blokes.

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