"Joe, why are you doing this?"

That is a question Joe Lieberman will hear again and again from old friends, as he mounts his "independent" campaign for the Senate seat his own party voted on Tuesday to take away from him.

And there is no compelling answer Joe can give.

Joe insists he's a progressive Democrat in the mainstream of the party and has a voting record to prove it. But Ned Lamont is a progressive (i.e., liberal) Democrat, and the Connecticut party chose him as its Senate nominee, not Joe.

Joe could say Iraq is the dividing line and the critical issue facing America. But Tuesday's primary was a referendum on Iraq, and the Connecticut Democratic Party voted to declare itself antiwar. And Joe does not even intend to run as a war Democrat in November. For he knows it would drive away an even larger share of the Democratic and independent vote than he lost on Tuesday.

But if he will not run as a principled pro-war senator, what, then, is the argument for re-electing Joe? For the transparent conclusion is that his independent campaign is simply about Joe's unwillingness to accept the verdict of his party and give up his cherished Senate seat.

Thus we find Joe declaring, in his concession speech where he announced his independent candidacy, that the true great divide between him and Ned Lamont is on the burning issue of -- civility in politics.

"I am, of course, disappointed by the results," said Joe. "I'm disappointed not just because I lost, but because the old politics of partisan polarization won today. For the sake of our state, our country and my party, I cannot and will not let that result stand."

Joe is running to save Connecticut and America from the savage politics of Ned Lamont?

Joe is a nice and decent man, with many friends across this town, but this is just not sustainable.

First, it is a slur on the Democratic Party of Joe's home state, which bought into Lamont's supposedly low-road tactics. Second, to strip votes from Lamont on the issue of his "politics of partisan polarization," Joe will have to rip into the Democratic nominee for running a dirty and divisive campaign, which is certain to enrage all the Democrats working to elect Lamont.

Third, Lamont is a "Pepperidge Farm" candidate, in the witty phrase of columnist Mike Barnacle. He did not call Joe a warmonger or a fascist, or run Willie Horton ads against him.

Fourth, if Lamont won only by McCarthyite tactics, how does Joe explain why every national and state Democrat -- including Bill and Hillary Clinton and Al Gore -- is hastening to endorse Lamont? Continued...