No Child Left Behind (NCLB) was only one of George W. Bush's mistakes. The basic fact of NCLB is that if you cannot be held back for not doing your school work, you do not learn. All children know this in kindergarten, that they can go to the next grade no matter what.
A child needs incentive to work and learn.
If you are held back for not learning, you will work hard to go to the next grade. We need to be able to hold children in a grade. Thus they will work to go to the next grade.
We will have children who can read and do math at grade level, instead of ones who graduate from high school who can't read and do math.