I’m chuckling over the anti-incumbent angst getting credit for the probable defeat Tuesday of longtime U.S. Sen. Arlen Specter of Pennsylvania.

Specter served for three decades as a Republican. Then he changed parties in 2009. He became a Democrat, just like that. Give the man credit for being honest: He didn’t stand a chance of being elected as a Republican, so he changed parties — and admitted to it!

So now he’s run into a Democratic buzzsaw in the form of Rep. Joe Sestak, who has presented himself as a real Democrat, not a pretender like Specter.

TV ads have shown Republican President Bush endorsing Specter’s re-election in 2004 and Democratic President Obama proclaiming his “love” for Specter in 2010.

I’m not convinced that anti-incumbent fervor is at play in Pennsylvania. What Keystone State Democrats are suggesting is that they don’t trust Specter, and they dislike his jumping onto their party bandwagon for purely self-serving reasons. He wants to stay in the Senate and voters are seeing this move as a cynical attempt to cover his rear end.

It’s true that Specter, who once was a Democrat before he became a Republican all those years ago, has been called a Republican in Name Only (RINO). Democrats now are labeling him a DINO — which translates into calling someone a politician without principle.