Nate Silver: "Specter's Switch More Insult Than Injury to GOP"

Nate Silver:

Senator Arlen Specter of Pennsylvania has decided to become a Democrat.

This strikes me as being bad news for the Republican Party more than it is good news for the Democrats. Back in January, I described a process which I labeled the Republican Death Spiral:

Thus the Republicans [...] are in something of a death spiral. The more conservative [...] their message becomes, the more they alienate non-base Republicans. But the more they alienate non-base Republicans, the fewer of them are left to worry about appeasing. Thus, their message becomes continually more appealing to the base -- but more conservative, partisan, and strident to the rest of us. And the process loops back upon itself.

This defection, coming at a time when historically low numbers of Americans are identifying themselves as Republican, would seem to be a manifestation of said Death Spiral. These problems, indeed, were particularly acute in Pennsylvania, where many of the state's more moderate Republicans had re-registered as Democrats to vote in the state's extremely contentious primary between Barack Obama and Hillary Clinton. Thus, given an extremely conservative Republican electorate, Specter appeared to be an underdog against his extremely conservative primary challenger, Pat Toomey, and switched parties in order to increase his odds of survival.

But this is not necessarily an unmitigated win for the Democrats. Unlike Jim Jeffords' switch in 2001, this does not affect who controls the Senate Chamber. Rather, it merely nudges the filibuster math, which has always been somewhat fuzzy. While the Democrats will have a nominal total of 60 votes once Al Franken is seated, the Senate's fortunes will still be determined by a group of about a dozen moderate senators from both parties (including Specter), just as it was before.

The real question is -- how often will Specter's vote change as a result of this? Specter was already voting with the Democrats on some issues, like the stimulus, and he said in his statement today that he will continue to vote against the Democrats on at least one other high-profile issue, the Employee Free Choice Act. If he goes from voting with the Democrats 40 percent of the time to 60 percent of the time, that is not so terrific for them, particularly if the 60th seat raises expectations and lends credence to Republican claims about the need for divided government.

But of course, Specter can't be too cute about this, or he might have primary problems on the left. The Republican nominee is probably going to be Toomey, who will be an underdog against any sentient Democrat. Why should the Democrats settle for a Liberdem when they can probably get Pennsylvanians to elect a mainline Democrat along the lines of Bob Casey? Specter's cooperation on key issues like health care and cap-and-trade would now seem all but assured -- but then again, Democrats could perhaps already have expected such cooperation to begin with.

Unless Specter becomes a fairly liberal Democrat (perhaps with one or two exceptions like EFCA) his party switch today is something which might have more symbolic than actual impact.

Howie P.S.: H/t to Mike Kato.