Just moved so I'm still threading my way around a maze of boxes and I'm getting my wi-fi from the Starbucks around the corner (which wouldn't be so bad if I didn't hate their coffee), so this won't be much of a post but the Matt Yglesias argument Joseph alludes to just doesn't hold up.
There is plenty of support for merit pay among center and right segments, people who are taking Yglesias's exact position here, so his statement is wrong when applied to the general population. Of course, Yglesias is taking about fighting among progressives so the anti-tax line makes even less sense.
Put bluntly (because my laptop's almost out of power), Yglesias is trying to explain why so many progressives are offended by his movement reformer stand without admitting that he might be the one contradicting progressive principles.
56 minutes ago