In my opinion vouchers are nothing more than another way to latch onto the government tit.
Look up the stats on charter schools in DC. They are scary. More than 1/2 of all charter schools in DC perform below DC public schools. After 5 years, the charters of low performing schools are revoked, but the charters reform under new names and new management and oh my the money comes rolling in.
Here's my favorite scenario. Let's give vouchers to parents to use for supplies for home-schooling. There have been enough stories of welfare mothers having extra kids for the extra cash. How long would the lines of welfare mothers be holding out their hands for $$ claiming that they are homeschooling? It would probably outnumber the crack addicts, but not by much.
Yes, I am cynical. Been around too damn long to not be. Not everyone is like "us" normal people. Some parents are evil and looking for mo' money, mo' money, mo' money at every corner.
*sigh* Yeah.
OTOH, I've searched the Constitution in vain for any reference to education being a Federal responsibility.
Maybe I missed it?