John McCain told the NAACP this morning that after decades of broken promises by the nation’s public school systems it is time to give all parents an easy choice of public and private schools. He is right, so long as he doesn’t propose a private school choice program at the national level.

The merits of wide-open parental choice — and the basic justice of it —are compelling, but the Constitution mentions neither the word “education” nor the word “school.” Congress and the president simply do not have a mandate to create such a program. More than that, a national private school choice program risks extending pervasive government regulation over private schools from the Potomac to the Pacific, homogenizing the options available to families and thus defeating the entire point of school choice. It is far better and safer for presidential candidates to tout the merits of school choice and encourage their state-level counterparts to put these programs into place. In that way, the varying experiences of the states – the so-called “laboratory of federalism” – can help to identify and eliminate problems in their implementation.