Ravitch: Is Common Core legal?

In her latest blog post, noted education writer Diane Ravitch, a best-selling author and former official in the senior Bush's Department of Education, questions whether Common Core Standards are legal:

When the Department made grants to professional groups of teachers and scholars to create “voluntary national standards,” I made a point of never interfering in their work. I extolled the value of having standards that states, districts, and schools might find useful but made clear that the decision to use or not to use the standards was strictly voluntary. There was no thought that the Department could advocate for the standards or use money to bribe states to adopt them. That would have been illegal.

Her post includes the wording of the actual law.