Gregg Birnbaum was the well-liked political editor of the New York Post, a 17-year veteran of the paper. Until yesterday, when he left abruptly. The reason, we hear: he got sick of NYP chief Col Allan's obnoxious behavior.

We spoke to Birnbaum, who confirmed that he is "no longer employed" by the Post. But the backstory, according to insiders, is dramatic. Sources say that Birnbaum got into a huge argument Monday night with Col Allan, the paper's famously boozy and abusive editor. After the curse-filled blowup—which apparently had something to do with coverage of Obama's tax plan—Birnbaum left the office. For good.

Newsroom arguments are common. But for Col Allan, this is a pattern. We've been hearing reports from insiders all year that the Post's ongoing staff exodus was due largely to Allan's "awful," bullying management style. It's damn near impossible to find anyone outside of Rupert Murdoch's office to say a kind word about Allan's embarrassment-filled reign at the paper—particularly not over the past couple of years, when circulation has plummeted, lawsuits have characterized the newsroom as a racist, sexist hellhole, and even admirers of the Allan's particular brand of flair have consistently started grumbling that he's lost his editorial touch. Even Liz Smith called him an "absolute total shit."

There's no word yet on what the paper will do for a political editor now. We'll send our condolences in advance to whoever gets the honor of taking the job. At a certain point, it's fair to ask: What does Rupert Murdoch see in Col Allan, any more? We hear Australia is nice this time of year.

[Photo of Allan via Patrick McMullan. Photo of Post newsroom via CJR]