Lieberman’s critics are well aware of his largely liberal voting record. And they have not shown the same fury for the other Democratic moderates who have expressed wariness at the prospect of a public option, like Sens. Ben Nelson of Nebraska, Mary Landrieu of Louisiana, Evan Bayh of Indiana and Blanche Lincoln of Arkansas. Asked about Lieberman’s stance, Senate Majority Leader Harry Reid of Nevada emphasized that, “Joe Lieberman is the least of Harry Reid’s problems.”

Yet it’s Lieberman and Lieberman alone who elicits the particularly unhinged outrage of the sort regularly on offer on liberal blogs and by partisans like Begala…

But such facts don’t matter to the Lieberman haters. They still haven’t forgiven him for not flagellating himself over the Iraq war, thereby refusing to follow in the steps of his Democratic colleagues and most liberal pundits. And while hawkish Democrats have reason to be angry about his endorsement of John McCain for President last year, Lieberman never promised that he would endorse the Democratic nominee.

Lieberman was reelected to the Senate as an independent and he has behaved like one. This understandably angers the partisan purists of the Democratic left, who, like their counterparts on the right, are only too happy to apply the term “traitor” to anyone who disagrees with them. And as they purge Lieberman, Democrats cannot recognize their hypocrisy in mocking Republicans over the rift in the 23rd Congressional District race, where a liberal Republican bowed out due to conservative pressure and endorsed the Democratic nominee.