So, obviously, I'm not going to like this kind of post from Megan, which she has one or two of a week. Look, a big part of Megan's brand is taking shots at liberals, and that's ok-- she's a libertarian, and a conservative one, and I expect nothing less. She does it better than most. While I can't quite understand the utility in writing this same kind of post over and over again, that's almost certainly a product of my ideological leanings-- I don't get tired of Yglesias carving up conservative nonsense, after all. Everybody has their niche.
No, here's the problem with this specific post: it's a part of a common attitude that undermines democracy. It's always going to be in vogue to point out the naivete of people who, you know, expect politicians to do the will of the people. It's a pretty cheap point, right? "Hey, democracy doesn't actually work the way it's supposed to." Plenty of bloggers do it, I'm sure I've done it. The problem is that it has a self-fulfilling edge to it. Megan here mocks liberals for thinking that Obama might actually live out the dictates of democracy and honor the commitments and ideals he ran for president for. But her incredulity empowers his abandonment of those things. The more people say "you can't expect politicians to do what they've promised," the more you undercut the expectation that politicians actually have to do what they say. When the expectation becomes failure for politicians to live up to any promises, you're effectively excusing that behavior.
The people who actually expect politicians to live up to their word are exactly the people we shouldn't be discouraging, and certainly not for the benefit of appearing world-wise or savvy. Like I said, it certainly isn't on Megan alone. This happens all the time; the pose of the person calling others out on their idealism is a common trope. But it isn't just talking about damaging democracy, it is damaging democracy. A certain degree of idealism is a prerequisite for functioning democratic governance. Real democratic government is a hard enough venture as it stands without principled people stacking cynicism against it.