The radicals took over the schools, and nobody stopped them. Now it will take a while to shed them.
All school districts in the U.S. are independent, there are no Federal school systems. They can all refuse to take Federal money any time they choose and do away with all the strings attached to it. They don't, instead they demand more money from the Fed; vouchers are just another string. Poor neighborhoods aren't going to bus anybody off to elite private boarding schools in any mass numbers, and the numbers of good teachers and small class sizes aren't going to a result of vouchers. That's just silly rubbish propaganda. Any school district in the U.S. can do a lot better all by themselves, by simply telling the Feds to shove it and set their own standards.