A report out of Israel quickly made the rounds in the U.S. a few days ago, noting that several prominent Republican leaders — Mitt Romney, Mike Huckabee, Newt Gingrich, Michele Bachmann and others — would join media clown Glenn Beck for a rally in Israel. Fortunately, the rumors were wrong — the Republicans mentioned in the report quickly announced they had never accepted the invitation and would not participate.

Good move. Beck has organized the event (a) as part of some bizarre take on End Times theology; (b) to make some cash selling event merchandise; and (c) to give him a p.r. boost as he makes the transition from Fox News. GOP leaders are wise to keep their distance.

The problem is Sen. Joe Lieberman (I-Conn.). “I’d love to participate,” he said this week. “It’s just going to be a rally to support Israel and the U.S.-Israel relationship.”

Dana Milbank had hoped for more.

Joe Lieberman, first Jew on a presidential ticket, was embracing Beck, the leading purveyor of anti-Semitic memes in the mass media. One of the most visible Jews in America was making common cause with a man who invoked apocalyptic Christian theology in promoting his rally in Israel.

I admire Lieberman, and I’ve defended him over the years when he defied party and faction. But if he shares a stage with this creature, he will surrender the decency that has defined his public life.

Milbank’s column is generally a good one, but there’s one key angle to this on which I think he’s wrong. The suggestion in the piece is that Lieberman’s willingness to join Beck in Israel is simply a lapse in good judgment.

I disagree. This is more of a denouement of Lieberman’s years-long slide into routinely bad judgment. “Surrender the decency that has defined his public life”? Was Milbank listening to Lieberman in January?

The mistake isn’t just Lieberman’s willingness to pal around with Beck; the mistake is expecting more of Lieberman in the first place.

For what it’s worth, when pressed by Milbank, Lieberman hedged on joining with Beck at the event. Soon after saying “I’d love to participate,” the senator backpedaled, telling Milbank, “Am I going to go? I don’t know. I’ve got a lot of other things going on.”

I’d like to see Lieberman show some decency here and turn Beck down, but either way, I won’t be surprised.

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Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.