Rupert Cornwell: Republicans face up to Specter of a grim future

Out of America: Senior senator's defection may deprive his old party of its last political weapon: the filibuster

How much further can the Republicans fall? In 2006 they lost control of Congress. Last year they lost the White House. And now they're about to lose their last bit of serious political weaponry: the filibuster.

In one shape or another, this classic legislative blocking device of talking a bill to death exists in almost every parliamentary democracy. Nowhere, though, does it enjoy a quasi-mythical status as in the US Senate. For that we can thank Jimmy Stewart, who, as the innocent and virtuous Senator Jefferson Smith, staged the most famous of all filibusters, albeit a fictional one, in Frank Capra's 1939 movie Mr Smith Goes to Washington.

In fact, the tactic had been around since the 19th century, and Capra's version was probably inspired by the mid-1930s antics of Huey Long, the populist and autocratic governor and senator from Louisiana who once spoke for 15 hours non-stop against a bill he thought did not do enough to help the poor, entertaining his non-existent audience by reciting Shakespeare and his favoured southern recipes.

Filibusters really came into their own, however, in the 1950s and 1960s, as the last resort of southern senators opposed to civil rights legislation. The two great claims to fame of Strom Thurmond of South Carolina are that he was the only man to serve in the Senate when he was 100 years old, and that he staged the longest ever individual filibuster, in August 1957 against a bill enabling blacks to exercise their right to vote. It lasted 24 hours and 18 minutes and featured Thurmond reading verbatim the voting rights of all 48 states. (Hawaii and Alaska had not yet joined the Union.) He kept going with malt tablets and a steak sandwich. He had also put in a long session in the Senate steamroom beforehand, so that he could drink during the marathon without a bathroom stop – though some scholars still insist he wore a nappy.

On paper, filibusters are more common than ever in today's partisan, polarised Washington. The more mundane truth, alas, is that they never actually happen. No modern Thurmond talks through the night to an empty chamber. Nor, for group filibusters, are rows of cots lined up in the hallways for senators to grab an hour or two of sleep between shifts on the Senate floor. Instead a "cloture" vote is almost automatically held on any contentious bill. If it doesn't get the required three-fifths support in the 100-member Senate, the measure is quietly dropped to save everybody's time.

For critics, this 60-vote super majority required for the passage of important legislation makes a mockery of democracy, by allowing a minority to thwart the will of a clear majority. Its defenders, on the other hand, insist that filibusters are an essential brake to stop a body that prides itself on its gravitas from acting divisively or in unseemly haste. No one, however, disputes that they are a powerful weapon for a minority party. Not for 30 years, since Democrats ruled the roost in Jimmy Carter's day, has one party had a filibuster-proof 60 votes in the Senate. But that may soon change.

The defection last week of Arlen Specter, the 79-year-old Pennsylvania Republican, to the Democrats gives the latter 59 Senate votes. If Minnesota's supreme court certifies the former comedian Al Franken as victor of last November's cliffhanger election in that state, as everyone expects it to do in a few weeks, the Democrats will attain the magic 60.

But the Specter case in particular is far more than a matter of numbers. Admittedly, he's a moderate who has often strayed from Republican orthodoxy. But to change party in one's impetuous youth, or even in calmer middle age, is one thing. To do so when you're almost 80, after nearly three decades of service in the Senate, is quite another.

Specter had had enough. By his own admission, the survival instinct played a large part. In his campaign for re-election in 2010 he was facing defeat in the Republican primary at the hands of a right-winger with little hope of winning in an increasingly Democratic state. His best bet, he calculated, was to become a Democrat himself. But far more important, he simply no longer felt at home in the party.

The Republicans' predicament is like that of the British Tories in 1997, only worse. Like the party led by John Major, they have run out of ideas after a generation of dominance. Today, America is as fed up with them as Britain was with the Conservatives a dozen years ago. At least, however, the latter bequeathed to their Labour successors a reviving economy. Obama inherited the biggest economic mess since the Depression, and one largely brought about by the anti-government, "the markets are always right" philosophies of the Republicans.

Rule one of politics, as of life is: if you're in a hole, stop digging. Not these Republicans, however. Their mistake, the rump that remains seems to have concluded, was not that they were too conservative, but that they were not conservative enough. So they keep digging, opposing in lockstep every policy of a hugely popular President as he tries to clean up the mess they left behind. Like Tony Blair in his pre-Iraq pomp, Barack Obama is not only a very skilful politician. Because of the calibre of the opposition, he is also a very lucky one.

Pennsylvania's senior senator is one of millions who is abandoning his party. In Congress, Republicans from Specter's north-eastern US are now an endangered species. Less than a quarter of Americans identify as Republicans; geographically, the party's appeal is limited to the Deep South, the Great Plains and the conservative west.

And now they're about to lose the filibuster. True maverick that he is, Specter celebrated his first day as a Democrat by voting against his new party on a budget measure. But it won't always be like that. Jefferson Smith, where are you?