Nemesis.

David Weigel describes his fall from grace:

But I was cocky, and I got worse. I treated the list like a dive bar, swaggering in and popping off about what was “really” happening out there, and snarking at conservatives. Why did I want these people to like me so much? Why did I assume that I needed to crack wise and rant about people who, usually for no more than five minutes were getting on my nerves? Because I was stupid and arrogant, and needlessly mean. Yes, I’d trash-talk liberals to Republicans sometimes. And I’d tell them which liberals “mattered,” who was a hack, who was coming after them. Did I suggest which strategies might and might not work for liberals, Democrats, and the president? Yes, although I do the same to conservatives — in February, for example, I told many of them that Scott Brown’s election hadn’t killed health care reform, and they needed to avoid dancing in the endzone, because I was aware of what liberals were saying about how to come back.

A lot of this sounds true.  Weigel claims to be a conservative, but he experienced the same need to mirror his new friends when he went to a new place, and so dropped his previous persona. In fact, he may have become more liberal than anyone else in order to show that he had dropped his previous commitments. This sounds like the typical Washington D.C. arc, and explains how banner-chasers like Weigel often move from their conservative roots to being lauded by their new liberal friends as "growing."

Note that Weigel's evolution began before he joined Journalist.  He had voted for Obama and was a supporter of gay-marriage and open-immigration while at Reason.

On the other hand, as a convert, he was never really going to be part of the inner sanctum.  There was always going to be a suspicion that he was simply the unprincipled banner-chaser that he seemed to be.  So, if anyone was going to get outed, it would be him.

Sophocles could not have written a better script.