Donald Trump’s presidential campaign has not been driven by detailed policy papers. But on one issue at least, his position is clear: He hates the Common Core State Standards. They are, he says, a “total disaster,” and he promises to abolish them upon assuming the presidency, because education “has to be at a local level.”

This is revealing, and not just because it shows Mr. Trump’s ignorance of how American education actually works. He is promising to solve a problem that doesn’t exist by using power the president doesn’t have. His plan may also have the unintended effect of stultifying American greatness.

The president can’t end the Common Core, because the federal government didn’t create the Common Core. Governors and state boards of education developed and voluntarily adopted the standards in reading, language and math. Some states subsequently un-adopted them, as is their right. When Congress passed a new version of the federal Elementary and Secondary Education Act last year, it prohibited the secretary of education from requiring or even encouraging states to adopt any uniform standards, Common Core or otherwise.

Mr. Trump has another claim about education: that America’s weak educational results will be improved by returning power to local school districts. That’s a notion, widely held, that is at odds with research, common sense and the education agenda of every president, Republican and Democrat, for the past 40 years.