Oh, it's going to Jonathan Chait, alright. But which to choose? His terrific takedown of doubletalk at the Weekly Standard? His canny call of tribalism on Abe Foxman? Both are good...but if pressed, I might have to say his pithy, perfectly titled quotation pull-out from a NYT story.
As a sometimes wannabe sabermatrician and proud r.s.bb alum (hey, non-baseball fans, don't go away -- this is for you, too), however, I do have to chide Chait on one thing. Not his main point about Juan Williams, but about his failure to realize that replacement level is below average, not equivalent to it. An average player (think maybe Aubrey Huff over his career; I'm not going to even speculate about who might be an average pundit) has considerable value. A replacement level player or pundit has little value, because there are plenty more as good or better available. The key concept behind this, from Bill James, was that the distribution of talent among major leaguers is not distributed along a normal curve; it's taken from the extreme right edge of the curve, so there are far more average than above-average players, and way far more replacement-level players than average players. The same thing should apply to college football, and even more so to the NBA.
Which brings me to Matt Yglesias, who got it exactly right: Juan Williams is a replacement level pundit. I don't think he's actively awful, but there must be a good fifty to a hundred people who can step right in at NPR and do as well or better. That's not nothing; there are plenty of times a major league team runs a sub-replacement level guy out there for 500 PAs, and that'll kill your team quickly. But it's not average, either. NPR can do better.
(Hey, I made it through almost a whole post about replacement level players with hardly any cheap shots at the expense of Brian Sabean. Not quite ready to forgive him for everything, but, hey! Cody Ross!)