Pick Your Poison, Arlen

It can't be much fun being Arlen Specter these days:

But the issue puts Specter in a particularly tough position that is a typical quandary for Republican moderates. Facing reelection in 2010, he hails from a state where unions are strong and the electorate is becoming more and more Democratic. That puts pressure on him to support the labor bill.

But Specter often faces opposition from fellow Republicans for being too liberal: In 2004, he faced a tough primary challenge from the right by Pat Toomey, who is now president of the Club for Growth, an anti-tax conservative group.

Toomey says that if Specter casts a decisive vote on the labor bill, "he virtually assures he will deal with a primary challenge and he hands the challenger a powerful issue."

The labor bill in question is the Employee Free Choice Act, a bill on which Specter's vote is absolutely crucial to the Democrats. Specter voted for cloture when EFCA came up in 2007 -- he was the only Republican to do so -- and has long had the backing of labor unions in Pennsylvania, most of whom endorsed him against Democrat Joe Hoeffel in his successful re-election bid in 2004.

But Pat Toomey, the conservative Republican who came closer to knocking off Specter in 2004 than Hoeffel did (losing by just 1.7 percentage points in the Republican primary) seems to be suggesting that he'll run against Specter if Specter votes for EFCA. Is Toomey -- or another conservative Republican -- a credible threat to Specter?

On the one hand, conservative Republicans tend to be out of vogue these days, especially in a state like Pennsylvania, who couldn't kick Rick Santorum out of the Senate fast enough in 2006. But the preferences of Pennsylvania's electorate as a whole hardly matter. Pennsylvania is a closed primary state, and so only Republicans would vote in the event of a primary challenge. With many of Pennsylvania's moderates having registered with the Democratic Party in order to vote in this year's Democratic primaries, Specter might not be able to count on much crossover support in the primary, especially with the Democrats liable to have a very interesting primary of their own taking place at the same time.

Still, Specter wouldn't seem to be in too bad of shape among his base. Quinnipiac has his favorability ratings among Republicans as 60 percent favorable, 21 perecnt unfavorable. Specter's ratings were notably poorer in 2004, when as of April of that year, Quinnipiac had measured his numbers as 52 percent approve, 31 disapprove among Republicans.

Toomey is now President of the Club for Growth, which came to his aid in 2004 but has a somewhat spotty track record of late, having lost 3 of the 4 Senate races where they backed a candidate in November. It's hard to know whether an organization that brands itself as the Club for Growth tends to do will be seen as a part of the problem or a part of the solution if the economy remains sluggish two years from now.

For the time being, however, Specter would seem to be at greater risk of losing in the general than in the primary. If he thinks he can guarantee himself labor's backing in the general in 2010, odds are that he'll call Toomey's bluff.