The conservatives argued that Lieberman’s loss revealed the extent to which the Democratic party has been taken over by the “net-roots” lefties and how it had become an unserious party in the war on terror. Lieberman was a rare Democrat hawk in support of the Iraq war and Bush’s conduct.

When he lost his seat some commentators went for interpretive overkill. Here’s Fox News’s pit bull, John Gibson: “Hang on, Dems. Here come the Pol Pots of your party. And if you were for national security, you are now emphatically not. Or else. Remember the mountain of skulls in Cambodia? It’s the Democrats’ new reality now that the anti-war rabble has tasted blood by taking Lieberman down.”

That gives you a taste of the partisan rhetoric now at large in America. But calmer voices made the case in more measured terms. Pro-war Democrats fear attacks from the anti-war Democratic base. Hillary Clinton, for example, could be seen as vulnerable in a surge of the Democratic party’s push for anti-war, anti-Bush purism — just as Democratic supporters of Lyndon Johnson were squeezed during the Vietnam war.

That 1960s far-left push helped re-elect Republican Richard Nixon in a landslide. Could it empower Bush and the Republicans this fall? That is precisely what some centrist Democrats fear: another defeat snatched from the anti-Bush jaws of victory.

The Republicans, moreover, can be relied upon to use Lieberman’s defeat as a warning to security-minded independent voters not to vote Democrat. Dick Cheney’s typically subtle response (that ousting Lieberman sends a dangerous message to the enemy) will be a Republican reprise this October.

So is the Lieberman loss a disaster for the Democrats? There are several reasons for being sceptical. The first is Lieberman himself. He wasn’t just pro-war. He rarely criticised the Bush administration’s handling of the conflict in Iraq and even suggested that any criticism was somehow illegitimate and unpatriotic in wartime.

That puts him in a more craven position with respect to Bush than even most Republican senators. Republicans such as John McCain and Chuck Hagel have been much more candid in their criticism of the president. It’s understandable that Democratic primary voters wanted to have a senator who functioned as a member of an opposition party, rather than as a poodle for the president.

And so their vote is not necessarily a rabidly left-wing sign. Lieberman’s loss wasn’t that huge either, suggesting that the anti-war sentiment, even among the Democratic base voters, is not overwhelming. And he has a small chance of pulling off a victory in November as an independent.

To complicate matters, and there is no polite way of putting this, Lieberman is sui generis. He is a pompous, self-righteous ass. His moralising and self-importance, his lame performance in the 2000 election (which gave him an even more inflated sense of his own gravitas), and his enmeshment with the Washington establishment, does not fit the mood of a restive electorate.

His ousting may have as much to do with a “kick the bums out” mentality than any profound reshaping of the Democrats. Hillary, with a shrewdly pro-war but anti-Bush message, has no such problems in her home state. Several other incumbents, Republican and Democrat, were tossed out in primaries as well, including one of the most left-wing, anti-war members of the Democrats, Cynthia McKinney. No one is predicting that her crushing defeat means a rising conservative tide among the Democrats.

Lieberman’s defeat could, in other words, presage something else. The public is deeply unnerved by the war in Iraq. It has grown seriously disappointed in Bush. A simple explanation for Lieberman’s defeat is that voters threw out a senator who seemed closest to the president. The centre in the country, one increasingly besieged by the extremes on either side, wants to fight this war competently. Lieberman’s subservience to Bush’s errors wasn’t helping anyone but the partisan Republican machine.

Insofar as Lieberman was providing cover for Bush he was helping the US lose this war, not win it.

The foiled attacks on American/British planes last Thursday will also help remind Americans that the threat from terrorists is not over. The fifth anniversary of 9/11 is looming as well. What Americans are looking for is neither subservience to Bush’s incompetence nor an isolationist denial that they face no real dangers.

Americans are increasingly tired of being told by their president that he has the will to win the war; they are more interested now in whether he has the skill to do so.

That’s why the most promising contenders for 2008 are McCain, Rudy Giuliani and Al Gore. They are all grown-ups, with national security credentials and a history of knowing how the government works.

But Lieberman’s loss last week and potential success as an independent this November could also lead to a different and more interesting scenario. What if the Democratic left rejects Lieberman and, in the Republican primaries, the religious right rejects McCain? Both are too centrist for their party’s base. Both can reach out to the disenchanted in both parties and maybe form a new movement of the centre: a Ross Perot-style movement without Perot’s lunacy.

A couple of months ago I fantasised about a dream ticket that could both unite the US and rejoin the battle against Islamist terror with new vigour and integrity. An independent McCain-Lieberman ticket for 2008? Stranger things have happened. And, given the bizarre history of the past six years, stranger things no doubt will.

Times Recommends

• And lo, he ventured forth . . .
• Lying to your children isn't a crime
• A single way to improve IVF treatment