>>14
So, when have students that have been performing poorly in a public school, putting them in a private school makes them better students? By what standard are you measuring these students improvement? I certainly would take the criterion of the school itself to be biased, as they have a vested interest in claiming "superior" results. Public education is however, transparent and subject to oversight, whereas private education is not.
What assurance do you have that the private schools would be well equipped, well staffed, and is providing adequate care for its students? If you want to argue that parents would do research beforehand, I can argue about fraud, but the more likely response is that you'll assign the privilege of choice to the parent. In which case, I can argue that the parents have no real choice at all, as they must send their children to school, and their taxes pay for it. What libertarians would like to see is taxpayers money going into private pockets, and the "corruption" of school politics is relatively benign at a community level.
My experience with vouchers is they are an attempt to get a rebate for people who already send their children to private schools, out of their own pockets, since they don't use the public school system, they feel they shouldn't pay for it. This is a slippery slope, as it leads to not wanting to pay for roads they'll never use, compensation they'll never use, an army that they feel they don't need, etc etc.