A federal police force under any president, including Trump, is a chilling prospect. Law enforcement must be conducted by the state, not the feds.

That said, if this experiment dramatically reduces violent crime, then we have a possible solution for the capital city: the federal government gives D.C. enough money to duplicate this experiment permanently. (Note: the D.C. budget is federally funded, which is why the feds have to pay.)

That means hundreds of millions of dollars a year to pay for hundreds of officers whose sole duty is walking neighborhoods in combat gear and rifles. They will interact with residents in four-officer fire teams, but not have to respond to the everyday 911 calls that "regular" cops must.

If the federal government is not willing to ante up to permanently reduce violent crime in D.C., then this military show of force was only a stunt. And it cannot be duplicated in any other city because no other city can afford those hundreds of millions of dollars for roving fire teams.