I categorically disagree with your statement. I believe NCLB was a good idea. I believe it has been sabotaged by state and municipal education boards.
In my opinion, the basic premise behind NCLB is that there are a few very, very BASIC, essential skills that children need, before they graduate from school. The implication is that students need to be literate at the very least, and need to be able to do some basic math - adding, subtracting, dividing, and the like. The problem is that NCLB has no teeth - no one in Washington was masculine enough to actually enumerate those standards. Instead, the actual standards were left to the states to set for themselves, individually. Most states responded in bad faith. Some, for instance, responded by setting artificially low standards, so they wouldn't have to make any effort towards improving anything. Some states responded by manipulating results and playing fast-and-loose with facts, figures, numbers, and classifications of students in their yearly reports. Those were the choices they made. They then blamed the results on the federal act, as if they didn't have a choice, after all, but to respond the way they did.
Bollocks. The state of education in this country does indeed suck mightily; however, your local school board, and your state's education board, are perfectly happy to let it stay that way. Mostly out of laziness. This has nothing to do with some "conspiracy" to "dumb down" American kids, and everything to do with people just not caring.