The thing about the proposed Justice Department examination of Chicago’s police force, which the mayor called misguided before he said he welcomed it, is that it sounds less like a housecleaning than a whitewash. The mayor has already thrown the police superintendent off the back of the wagon. But Justice could turn the whole force inside out without getting to the root of the problem.

   A front-page story in Sunday’s Tribune—whose first section, including the editorial pages, was virtually a Laquan McDonald special section—got to the point: Chicago police officers “enforce a code of silence to protect one another.” Their union further “protects them from rigorous scrutiny.” The Independent Police Review Authority “is slow, overworked, and, according to its many critics, biased in favor of the police.”

A Justice Department probe into what’s wrong with the police department that stops with the police department would be like an overhaul of the police department that thinks it’s enough to fire the current superintendent and bring on the next one. An investigation that drills deep enough to matter would drill past the dysfunctional CPD into the civic bedrock that enables it.