The question on many minds these days is the impact of Sen. Arlen Specter's switch to the Democratic Party. The temptation is to say both "a lot" and "not much," because either answer pretty much applies.

The reasoning behind "a lot" is that this is simply the final -- or at least the most recent -- indignity for a Republican Party that has dropped from parity in voters' party identi-fication in 2004 to 7 or 8 percentage points behind, and that has suffered a net loss over the past two elections of 54 House seats and 14 Senate seats (including Al Franken's all-but-certain victory in Minnesota but excluding Specter's switch). And, of course, the GOP also lost the presidency.

Specter had never been a particularly loyal Republican, so why would anyone believe he would now become a loyal Democrat?

The decision by Pennsylvania's senior senator to bolt from the Republican Party was undeniably an act of extraordinary expediency by one of the most opportunistic politicians of this era. But his motivation underscores the larger point. Had Republicans taken a committee slot away from Specter or spurned him in any way, this party switch could be attributed simply to an act of pique. But that didn't happen. Specter didn't change parties out of spite or revenge, as some others have done. His move was simply about political survival -- no more, no less.

In National Journal's 2008 voting ratings, Specter had one of the eight-most-centrist records in the Senate. For him, that was both the solution and the problem. A voting record sufficiently moderate for a Republican to win a general election in Pennsylvania made him insufficiently conservative to win a Republican primary when challenged by a hard-right conservative. That's a Republican problem, not just a Specter problem.

And that fact brings us back to the implications of Specter's switch and to perhaps the only thing in the episode that Republicans can laugh about. Specter's denial to moderator David Gregory on NBC's Meet the Press that he had promised President Obama and others that he will be a "loyal Democrat" had to be greeted by side-splitting laughter in the GOP cloakrooms. In his many years as a Republican senator, Specter had never been a particularly loyal Republican, so why would anyone believe he would now become a loyal Democrat? Specter will be a loyal Spectocrat.

Specter was a key swing vote in the Senate when he wore a red jersey, and he will remain one now that he wears a blue jersey. Nothing has changed on that score.

The fact is that with Specter's switch and Franken's virtually inevitable win in the next month or two, Democrats will get their 60 seats. Getting to a filibuster-proof 60 on any given vote will still depend on the issue, though. If on a particular proposal Democrats can hold Evan Bayh of Indiana, Kay Hagan of North Carolina, Tim Johnson of South Dakota, Mary Landrieu of Louisiana, Joe Lieberman of Connecticut, Claire McCaskill of Missouri, Ben Nelson of Nebraska, Mark Pryor of Arkansas, and Mark Warner of Virginia as well as Specter and the 50 other Democrats, they won't need the help of the Senate's two remaining Republican moderates, Maine's Olympia Snowe and Susan Collins.

So Specter's switch doesn't change much of anything on the Senate floor, except whatever votes he might have given his party out of political expediency between now and what would have been his Republican primary next March, in an effort to fend off a challenge from former Rep. Pat Toomey. Now Specter doesn't have to pretend to be a conservative.

More important than whether Specter is wearing a blue or red jersey is whether Obama's job-approval ratings and the economic outlook provide the 10 or so centrist Democrats and the two Republicans in the middle enough cover to feel comfortable backing the president's agenda. If Obama's numbers are holding up and the economy really starts recovering later this year or early next year, as looks increasingly possible, then life will be easier for Majority Leader Harry Reid and Majority Whip Richard Durbin, regardless of which side of the aisle Specter sits on.

This article appeared in the Saturday, May 9, 2009 edition of National Journal.

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