Mayor Bloomberg has once again gone off-campus for a schools chancellor. His thinking: A good manager can make anything work.

This drives educators nuts, but cheers people who think educators have proven themselves incapable of fixing schools. There’s certainly reason for concern: K‑12 education hasn’t gotten much better for decades despite huge funding increases. For most of that time, educators have run the show.

On the flip side, putting people without chalk on their hands in charge is a relatively new thing. From anecdotal evidence, it doesn’t work much better.

David Brewer and Julius Becton, Jr., were former military top-brass hired to drill dismal districts into shape. Brewer, who headed the Los Angeles Unified School District, left after just two years when city politicos expressed a lack of faith in him. Becton met a similar fate in Washington, DC. Joel Klein came from a legal background and lasted much longer than Brewer or Becton, but given recent testing revelations it’s hardly certain that his tenure was much more effective.

Of course, none of this proves which resume is best. Indeed, a district leader needs both pedagogical knowledge and managerial skills. He must, for instance, decide which reading program to adopt while ensuring that the bills are paid on time.

That said, the biggest obstacle to success isn’t a superintendent’s experience. It’s that in public schooling political power — not learning — ultimately rules.

Consider Michelle Rhee. She had a pretty even mix of educational and managerial experience, having taught for three years and founded The New Teacher Project. She also appeared to be having success with the Washington, D.C. schools, seeing significant improvements on the National Assessment of Educational Progress. But her hard-charging ways aggravated the American Federation of Teachers and alienated many District residents. Now her boss, Mayor Adrian Fenty, is on his way out, and Rhee is already gone.

To know what kind of leader is best able to maximize learning, we must disconnect politics from education. We need school choice and educator autonomy so that political considerations don’t decide who leads. Performance must decide that, with leaders sinking or swimming based on whether their schools work well enough to attract customers. Only then will the best education leaders — not political operators — rise to the top.