Josh Cowen is the voucher lobby’s worst nightmare. He was a participant in voucher research from its beginnings. He knows the research as well as anyone in the country. He knows that vouchers have failed. And unlike many others in this tight-knit world, he declined to climb aboard the gravy train funded by billionaires. He determined to tell the truth: vouchers hurt kids.

In this article, as in many others that he has written, he explains that there is no upside to vouchers. They subsidize kids already in private school. They harm the kids who leave public schools. They defund the public schools that the vast majority of children attend.

He begins:

What if I told you there is a policy idea in education that, when implemented to its full extent, caused some of the largest academic drops ever measured in the research record?

What if I told you that…