Strictly speaking, a President cannot cancel a law with a wave of his hand or the signing of a document. But he can sign an executive order decreeing that a given law doesn’t need to be obeyed. The difference is a mere technicality; the results are the same. One could also raise the argument that the entire law wasn’t rendered inoperative, only certain provisions. But invariably when this happens, it is to alter those provisions that were controversial in the first place. The Founding Fathers gave us a government where controversial matters were not to be decided by one person, but by the House and the Senate where the people are broadly represented. Of course there is a form of government where the leader does have the power to make, break or change the law. It is called a dictatorship.
Whether No Child Left Behind is bad law or not is a decision for Congress or the courts to make, not the President. The establishment of a Rule of Law is an essential requirement for any fair and prosperous nation to succeed. When laws once enacted by a congressional body are subject to executive change and bureaucratic interpretation you have “flexlaw”. Flexlaw is not a set of established laws at all; it is a set of whims. Obama and his Administration are transforming our land from a Republic into a DINO, a Democracy In Name Only. He must be stopped.