If there had suddenly been a big change in national test scores, downward, I would believe that NCLB had had an effect like you say. But the schools were not all just peachy until Bush came along. They’ve been useless sewers of ignorance for a long time. NCLB may not have helped but it can’t be the only thing to blame.
I'm not saying NCLB is the reason many public schools are failing, but I am saying that NCLB is making many public schools, especially challenged inner city public schools, much, much worse.