Joe Lieberman is a traitor to his party, and to the causes that he has championed.

Call him Benedict Joseph.

There he was, unctuous as always, with that fake aw shucks routine, asking, “What, after all, is a Democrat like me doing at a Republican convention like this?”

There’s an easy answer to that one.

You shouldn’t have been there, Joe, and you certainly shouldn’t be construed as a Democrat.

If Lieberman’s appearance proved anything, it proved how little distance there is between a DLC Democrat and a Republican. It sure is a short walk.

And he did it so smugly.

With utmost paternalism, he called Barack Obama a “young man.”

And with astonishing lack of principle, Lieberman spoke directly into the camera to address what he called “my fellow Democrats and Independents,” urging them all to vote for McCain.

Joe Lieberman used to be a fighter for civil rights.

Joe Lieberman used to have a 100 percent rating from NARAL.

Joe Lieberman led the latest Congressional charge on global warming.

But now he’s thrown in with the party that is 180 degrees from these positions.

In this role Lieberman resembles no character so much as Rabbi Bengelsdorf in Philip Roth’s The Plot Against America, who shamelessly sucks up to Charles Lindbergh.

That’s him. Shameless Joe.