U.S. Secretary of Education Arne Duncan has put in writing why he’s rejecting California’s request for a waiver under the No Child Left Behind Act.

It’s quite simple, really: You didn’t follow all of our rules.

In the letter to California Board of Education President Michael W. Kirst, dated today, Duncan acknowledges that he has the power to grant a waiver if it will “increase academic achievement and improve the quality of instruction for students.”

But he says California’s request, which wanted all of the flexibility but without agreeing to all of the federal department’s strings, didn’t meet that “high bar.” (California’s request skipped the teacher-evaluation component of the federal waiver process.)

“I believe that a State must agree and be prepared to take on the rigorous reforms required by all of the principles of ESEA flexibility in exchange for that waiver,” Duncan wrote.