Earlier today Pennsylvania Sen. Arlen Specter decided to join the Democratic party. The standard joke appears to be: "So what's new?"

Specter has been increasingly at odds with rank-and-file Republicans -- especially where it matters -- in his home state. Numerous polls showed Specter upwards of 20 points down in a GOP primary matchup against former congressman Pat Toomey. So, Specter held tight to his principle -- his principle being whatever it takes so that he remains a senator -- and decided to join the Democrats.

In the grand scheme of things, what does this mean?

Not much. Specter will vote whichever way the wind is blowing -- and that's nothing new for a guy who threw out his shoulder patting himself on the back for voting "not proven" in the Clinton impeachment case.

What this is is big trouble for the Democrats. With Specter along with the likely former funnyman Al Franken from Minnesota on their side (pending the outcome of Norm Coleman's court case), Democrats will have the magic number: 60. They won't be able to blame GOP obstructionism. Any political payola that Specter holds out for will be due to the fact that Obama now can't get a Democrat to go along with his radical agenda.

Some talking heads have suggested that Specter's decision demonstrates how the "big tent" of the Republican Party is getting smaller. That's not true. The tent didn't change -- the GOP leadership had promised to assist him (again) in his primary fight against Toomey. No, Specter left because it benefits him personally. No more, no less.