There is a spectre haunting the Republican Party — Arlen Specter, GOP Senator from Pennsylvania, who has announced that he is switching party affiliation and will now caucus with the Democrats and run as one in 2010.

The move brings the Democrats closer to a filibuster-proof 60 party votes — before Specter switched they had 58, with the Minnesota victory of former comedian Al Franken still being challenged by Republican Norm Coleman in the courts — even though almost everyone rates Coleman as having no chance of success.

The 60 votes wouldn’t be solid — Specter for example has made it clear that he won’t vote for the pro-union Employee Free Choice Act — but it would be crucially reliable for processes like confirming Obama’s cabinet choices, a process that the Republicans are filibustering. Coleman’s legal challenges on the Minnesota count are now the final barrier to this, which is why they’re being pursued at such length.

Specter is hardly a moderate figure, but he’s one of the last of the so-called “Big Tent” Republicans — he was first elected in 1981 — secular by inclination, willing to consider social policy on a case by case basis.

That attitude led him to be one of three GOPers backing Obama’s stimulus bill, and it was that vote that made it impossible for him to continue as a Republican.

In another chapter in that party’s multi-volume suicide note, Specter got a challenge from the Right for the upcoming Senate primary vote from former Congressman Pat Toomey, a social conservative who represented the LeHigh valley, an area where small-town Pennsylvania (“Philadelphia and Pittsburgh with Alabama in the middle” as James Carville remarked) really begins.

Toomey was on track to win the GOP primary easily — a measure of the degree to which the religious right have taken over that state party — but he would have lost the Senate seat to the Democrats, big-city Pennsylvania supporting Specter only to the degree that he’s willing to be an economic moderate. The GOP knew this, but didn’t care — there was more loathing in their heart for a colleague who dissented from the whole god ‘n guns package than there was desire to keep the seat.

The shaky Senate super-majority that Specter and — eventually — Franken gives Obama is more than they ever expected (strategists were working on the belief that they might get 56 seats in the 08 election). More importantly it gives the democrats a 2010 gain they weren’t counting on — Pennsylvania was an outlier. There are another five seats the Democrats have a good chance of taking, another two they could get, and only one or two they could lose.

That would potentially give them 65 seats — which means that Obama could work around some of the more centre-right (“blue dog”) Senators.

Doubtless some people in the GOP are thinking about this, but most of the rank-and-file don’t seem to have noticed it. I suspect that the fantasy version being sold — that Obama’s election has been a socialist take-over — is so complete that it doesn’t allow for any focus on the real process by which Obama could consolidate his power (potentially most importantly the power to confirm Supreme Court justices). How could he, if the place is already North Korea?

Should 2010 be a Democratic slam dunk, conservatives will have to start seriously thinking about whether the party is heading in the direction of permanent unelectability.

Specter indeed. Silly buggers. They might have geist.