I missed this when it was published Thursday. The Washington Post’s Philip Bump did a fact-check of sorts on a claim made by President Trump: “You hear about certain places like Chicago and you hear about what’s going on in Detroit and other — other cities, all Democrat run,” he said. “Every one of them is Democrat run. Twenty out of 20. The 20 worst, the 20 most dangerous are Democrat run.” It’s not clear how Trump is defining “most dangerous” in this context. So let’s look at two related sets of data compiled by the FBI: most violent...