If you want to see, like, six, really unconvincing, but really pissed-off and insulting arguments for vouchers, scroll through McArdle's place for awhile. It'll raise your blood pressure. At least until you're overtaken be sheer befuddlement.
Her argument, in a nutshell, is, "Either you agree that poor kids should be allowed to exit until the system works for them, or they don't." What? Since when do libertarians think making something cost money is the same as prohibiting you to do it? Poor kids can exit the system. They just need to become rich kids. But does Megan apply this theory widely? Does she agree that the Federal Government should pay for all Americans to have health insurance from any insurer, either public or private, that they want, at least until Aetna begins working better? Because if she does, then I've massively misunderstood her writing up till this point. If she doesn't, however, then her constant screech of hypocrite throughout this argument makes no sense -- particularly given that she has awesome, employer-funded insurance, while all millions of Americans are trapped on the individual market.
Indeed, unlike with vouchers, we actually know that being uninsured is bad for you, and that the poor have better outcomes when they're given full insurance. But, like with the schools, they -- not to mention many in the middle class -- are currently unable to purchase exit from their shit insurance -- or uninsurance -- systems. But then, systems don't seem to be much under analysis here. Megan's posts are remarkable for their lack of data as to why vouchers are actually superior. Which is because there is no data on that point -- vouchers haven't proven themselves in any of the largescale experiments we've conducted. What Megan is offering is "exit," not improvement. A big ladling of libertarian economic theory onto the trays of the poor. And if you're not down with that, well then, you hate the poor.