By Dean Hubbard, Kansas City Star Editorial Advisory Board Columnist

What’s with Joe Lieberman? Surely he’s not being duplicitous when he threatens to filibuster and kill a public option after promising Harry Reid that he would not block up-or-down votes.

We all remember when he came hat-in-hand on November 5, 2008 to plead for membership in the Senate Democratic Caucus. Was he being devious with the Caucus when he persuaded them to allow him to retain his chairmanship of the Senate Committee on Homeland Security and Governmental Affairs?

Similarly, he can’t be backing down, can he, on his assertion during his campaign for the Senate in 2006 that he was the best candidate to assure a public option?

Naw. It’s Halloween, and he’s just playing trick or treat with his Democratic colleagues.

Where I grew up in rural and poor Southeastern Washington my family and many of our neighbors had outhouses. The favorite trick among teenage boys on Halloween was to go around and push the outhouses over--on the door, of course, which made it even more fun if some hapless soul was inside. This ritual occurred year after year until someone wised up and after dark moved their outhouse to the other side of the hole.

That’s what the Democrats need to do with Lieberman. If Lieberman follows through with his threat and attempts to dismantle all the work that has gone into healthcare reform, he needs to step in it--big time. That means dismissal from the caucus, loss of his chairmanship and whatever other benefits come with being a chameleon.