President Donald Trump’s former attorney, Michael Cohen, may have been convinced by the Office of the U.S. Attorney for the Southern District of New York to plead guilty to a supposed violation of campaign finance law, but that doesn’t mean that what happened is actually a federal crime. In fact, neither the Federal Election Commission—which is the independent agency tasked with enforcing the Federal Election Campaign Act—nor its former commissioners would likely agree with the overaggressive view that the Southern District is taking. Indeed, the Southern District’s aggressive stance on this issue might have violated the Justice Department’s own policy....