Two posts by Josh Marshall take on the timing of the decision to fire U.S. Attorney Carol Lam as she was prosecuting Republican Congressman Duke Cunningham. According to the continuing excellent coverage by McClatchy,

In an e-mail dated May 11, 2006, Sampson urged the White House counsel's office to call him regarding "the real problem we have right now with Carol Lam," who then the U.S. attorney for southern California. Earlier that morning, the Los Angeles Times reported that Lam's corruption investigation of former Rep. Randy "Duke" Cunningham, R-Calif., had expanded to include another California Republican, Rep Jerry Lewis.

Noting this, Josh Marshall writes

What people tend to overlook is that for most White House's a US attorney involved in such a politically charged and ground-breaking corruption probe would have been untouchable, even if she'd run her office like a madhouse and was offering free twinkies to every illegal who made it across the border. Indeed, when you view the whole context you see that the idea she was fired for immigration enforcement is just laughable on its face. No decision about her tenure could be made without the main issue being that investigation. It's like hearing that Pat Fitzgerald was fired as Plamegate prosecutor for poor deportment or because he was running up too many air miles flying back and forth from Chicago.

He also expands on the timeline - turns out, it's not just that Lam was looking at more members of Congress, but the number three guy at the CIA was under investigation and the head of the CIA had just resigned related to the Cunningham case. There were a ridiculous number of high-ranking Republicans being investigated for just unbelievable corruption. Plus hookers. And yet the hubris of this administration is such that we're expected to believe that she just wasn't doing a good enough job on immigration. But the thing is, the traditional media was ready to accept that, and would have done so without the confluence of Talking Points Memo and other blogs, a Congress willing to investigate, and the purge victims getting pissed off enough to speak out against the lie that they had been fired for poor performance.

As Digby writes

One of the silliest conventions of modern journalism is that the press can't tell a story if "the other side" isn't screaming about it. Republicans are always screaming (and often are the ones feeding the scandal to the press in the first place) so it's very easy to find that hook. Democrats don't have the institutional infrastructure to successfully manufacture scandals and are often slow off the mark in seeing real ones, so the press doesn't feel they have any reason to pursue them. (And I guess stories about crass political patronage, even in the justice department, just aren't considered news anymore. That's a sad comment all by itself.)

There's some great reporting coming out now on this, and a few outlets like McClatchy and some California newspapers that covered Lam's "resignation" stand out as having seen the importance of the story early on. But, once again, most of the traditional media had no interest in making rampant Republican corruption into a story until others stepped up and forced their hand.