In a surprise White House appearance on March 27, US Attorney General Jeff Sessions announced his intent to make America’s cities less safe and more vulnerable to crime unless he gets his way. He didn’t say it quite like that, of course. In fact, he asserted the opposite, accusing so-called “sanctuary cities” of “mak[ing] our nation less safe by putting dangerous criminals back on the streets” and conditioning future grants from the US Department of Justice’s Office of Justice on certification by the recipient state and local governments that they are not “sanctuary” jurisdictions. Don’t get...