President Trump's urgency about the shootings on the streets of Chicago is welcome.

His threat to "send in the Feds" if Chicago can't get the violence under control is less welcome. As Heather Mac Donald writes in this morning's Wall Street Journal, policing is essentially a local function.

And, besides, Chicago's problems may actually be exacerbated by too much "help" from the Feds. The Obama Department of Justice is already in Chicago and that has hampered policing, Mac Donald maintains.

She writes:

A week before Inauguration Day, President Obama’s Justice Department released a shoddy report declaring the Chicago police guilty of a pattern of unlawful force. That report lacked the most basic statistical integrity and transparency; it failed to disclose any data that justified its conclusion. The feds recycled fabricated calumnies about the department, such as the outrageous claim that officers in Chicago do not care about solving black-on-black crime. It found police racism through the usual trick of ignoring crime rates.

Yet Mayor Emanuel has said, based on that ungrounded report, that he intends to sign a federal consent decree to put the Chicago police under a Justice Department monitor. Doing so would redirect scores of officers from fighting crime to writing reports. Federal monitors have an insatiable appetite for paperwork. Chicago taxpayers would likely face hundreds of millions of dollars in compliance costs, money that could be better spent hiring more cops and drilling them on tactics and communication skills.

Mr. Trump and his prospective attorney general, Jeff Sessions, should tear up the Chicago report and declare that the federal government stands behind proactive policing. The right message: The Justice Department will be vigilant in monitoring police abuses, but it understands that officers respond to the community’s demands for safety and order. Those demands come most fervently from high-crime areas, whose law-abiding residents beseech the police for freedom from drug dealers and unruly youth gangs. Messrs. Trump and Sessions should make clear that police officers need no longer fear that stopping and questioning people engaged in suspicious behavior will draw the condemnation of the federal government.

The bolding is mine. The idea that what Chicago needs is more monitoring from the DOJ rather than on-the-streets policing reminds me of these TV commercials.