Arlen Specter with his two options: become an independent like Lieberman or hope this Alaskan makes a few trips to PA. (Photo by Flickr user scriptingnews. Creative Commons License.)

With former congressman Pat Toomey’s revelation that he is seriously considering jumping over from the governor’s race to take on 16-term Senator Arlen Specter, the blogosphere is abuzz with possible scenarios.

Full disclosure: In 2004, I was the Issues Director for Congressman Joe Hoeffel who ran unsuccessfully against Senator Specter in the general election. Specter won that general by about 11 percent of the vote after squeaking by in the primary against Toomey. At the time, we on the Hoeffel campaign clearly liked our chances against Toomey better but considered it pretty unthinkable - at least early on - that the guy could win.  As that primary approached, however, and the polls showed some tightening, it became clear that it would be a dogfight.

Earlier today I was in touch with some former colleagues from that race and one local Democratic operative about some number crunching that the operative had done to compare the PA GOP electorate of 2004 with 2008.  Going county-by-county, his worked showed that while the GOP grew overall by about 13K between ‘04 and ‘08 (by contrast, the Democratic Party grew by over 700,000K after starting with a 500,000K lead in 2004), most of that growth was in counties that Toomey won or came very close to Specter.

Going county by county, he also extrapolated what the changes in registration totals would mean for each candidate.  For example, in Bucks County, Arlen Specter got 31,971 votes to Toomey’s 25,139 in 2004.  By 2008, the number of Bucks County Republicans had dropped by nearly 8 percent.  Simply assuming that Specter still gets 55 percent of the remaining votes means that he loses 543 votes from his overall margin.  Do this county by county and the result is that Specter loses almost half of his 17,000 vote margin.

And that assumes that the loss of Republicans in some counties and the gain in others is shared evenly between Specter and Toomey.  It’s not a big leap to say that almost all of the 8 percent of voters who are no longer Bucks County GOP voters were Arlen Specter voters.  So just by the numbers Specter seems to be in a tough spot.

Another of my colleagues from that race made the other point that the only reason Specter was able to cross the finish line ahead of Toomey in 2004 was because he had conservative icons George W. Bush and Rick Santorum dragging him across.  This time around, there won’t be any of those “we need Arlen Specter to get our Republican agenda passed” commercials to help him out.  In fact, I have a feeling that the new head of the Republican Party, might even mobilize his legions of followers against Specter.

So what’s left for Specter?

Matt Yglesias describes the senior senator’s dilemma quite well:

In the 2007-2008 congress Specter, no doubt in part as a token of appreciation for that AFL-CIO support, was the lone Republican to back EFCA. If he votes for it again this congress, it’ll be tough for him to win the primary. But if he votes against it, I think he’ll find it tough to win the general election when his support from Democratic-leaning interest groups vanishes. I doubt Specter will avail himself of this option, but the obvious solution would be to stick to his guns on EFCA and follow up his support for the stimulus by switching parties and, like Jim Jeffords, reposition ideologically somewhat. In other words, stop being a vulnerable moderate Republican and become a plain-vanilla Democrat with a safe seat. It would be pretty easy for Specter, as a Democrat, to beat GOP nominee Toomey in a general election. But beating Toomey in a primary without becoming too right-wing to carry the state will be tough.

What Yglesias misses about Pennsylvania, however, is that labor here might actually be willing to look the other way as Specter makes all of the anti-labor, pro-gun, anti-tax votes he needs to in order to win the primary.  Bringing home the bacon is a pretty big motivating factor for the traditionally Democratic-leaning interests groups that line up behind Specter.  And with his seniority not getting any smaller, Specter continues to be the master at delivering the oversize check.

Here are some other questions to consider.  If Specter does switch, does he switch to an independent or all the way to the D side?  If independent, would any of the big names - Sestack, Murphy - take the risk in the general of facing Specter and Toomey?

I guess we’ll get a tip of his hand based on his upcoming votes on the budget and the Employee Free Choice Act.  If he sides with the D’s, maybe switching is an option.  If he makes his traditional two-year sprint to the right, well, maybe he’s hoping that Sarah Palin will come down and shoot a few ads (and wolves) for him.