Republicans in disarray after Arlen Specter’s defection

All eyes are on Obama but the real story at mid-springtime is not how he has vaulted effortlessly over the lowest bar in political history - being a better president than his predecessor - but the collapse of the Republican opposition.

The sun has dipped low in the sky over the Republican Party as the 'Other Leading Brand'. A mere 21 per cent of the adult population now identify themselves as Republicans.

Last week the present low ebb of the party of Lincoln was vividly illustrated by the defection from its ranks of Senator Arlen Specter. This is a transition of prime political importance. Only six weeks ago Specter was insisting that "I am staying a Republican because I think I have an important role, a more important role, to play there. The United States very desperately needs a two-party system. That's the basis of politics in America. I'm afraid we are becoming a one-party system, with Republicans becoming just a regional party with so little representation in the Northeast or in the middle Atlantic."

But Specter is facing a difficult Republican primary, the opening act of his bid to be re-elected for a sixth term. The senator, who began his political career as a Democrat, is classed as a Republican 'moderate', meaning that he has had friendly relations with organised labour - powerful in Pennsylvania - and has decent views on issues such as reform of the criminal justice system.

Specter saw the writing on the wall, defeat in the primary by a far-right Republican zealot. Sensibly, he prefers to make his run under the ample Democratic banner, rather than get mangled in the tiny shark tank of a Republican primary attended only by people who want to see the country run by Rush Limbaugh and Sean Hannity.

The Republicans need Carrie Prejean no more than they needed Sarah Palin

This is a game-changer. With Democrat Al Franken finally certified as the winner by a few hundred votes against Norm Coleman in Minnesota, with Specter crossing the aisle and vice president Joe Biden in reserve, the Democrats can no longer hide behind the excuse of a Republican filibuster, as a way of saying that they can't put up 'divisive' bills, such as public enemy number one for corporate America: the 'card check' law that would make it easier (ie from the virtually impossible to the merely arduous) to organise a union. Even without Biden, they'll have the 60 votes.

Of course the real, ongoing divisions in America will relocate within the Democrat Party, so tremulous predictions by right-wing Republicans of a looming one-party state are silly. But Specter's move shows how rapidly the Republican Party has shriveled. Six months ago, 32 per cent of voters in the presidential election identified themselves as Republican.

Since then the Republican leadership has had one dumb idea after another, most conspicuously with the big 'No' on Obama's economic stimulus bill. Amid crisis, they have no ideas, beyond insisting that water-boarding captives is a terrific idea and saved America. They have no doughty champions. Governor Sarah Palin has been beached in unseemly wrangles with the father of her grandchild.

Her replacement as the far-right's Joan of Arc is Carrie Prejean, defender of the sanctity of marriage only between people of differing sex, pipped of her shot at Miss USA because of her honesty, now facing a mini-crisis because it turns out the Miss California Organisation paid for her breast implants. The Republican Party doesn't need Carrie any more than it needed Gov Sarah.

Souter was always an oddball – Bush Snr chose him thinking he was rightwing

But at this moment of crisis for the Republicans, there is a ray of hope that matters weightier than silicon implants will come to their rescue. Justice David Souter has announced he is stepping down from the US Supreme Court. At a relatively youthful 69, he says he’s sick of Washington DC and wants to go back to his log cabin in New Hampshire.

Souter was always an oddball, ever since George Bush Sr picked what he thought was a right-wing judge. To the Republicans' chagrin Souter swiftly disclosed himself to be of independent views and is now regarded as the second most liberal of the nine-person court, after Justice John Stevens.

If Obama nominates a liberal, the Republicans will have a serious issue to ride, to raise money on, and they can certainly stretch the definition of liberal to include anyone who doesn't have a ringing endorsement of torture, of the right to life, of the right to bear arms, on their judicial resume.

In line behind Souter as candidates for retirement or summary removal by the Reaper are Stevens, who turned 89 on April 20, and Ruth Bader Ginzberg, who just had surgery for pancreatic cancer. Two more liberals. Obama could well be nominating three in his first term. He no longer has the alibi of a threatened Republican filibuster as excuse to pick a 'centrist'.

Thus far he's faced no serious opposition from either the right or the left, even though the issue of whether to call Bush-era torturers to account has prompted polite liberal catcalls at the president for his transparent cowardice on this issue.

Fights over who should sit on the US Supreme Court are always serious. It’s an opening for the Republicans but one that will fervidly arouse its nutball contingent. For liberals it will be  a call to Obama to step up to the plate and really show what he's made of. Of course the irony is that Republican presidents nominated the two most liberal court members. And it was the Republican Eisenhower who nominated the legendary liberal William Brennan to the bench in 1956. ·