Hundreds of masked white supremacists descended on the nation’s capital, proudly waving Confederate flags during the 250th Independence Day celebration. The demonstrators were seen wearing hats emblazoned with the logo for the Patriot Front — a white nationalist group founded by Thomas Rousseau after the 2017 “Unite the Right” rally in Charlottesville, Virginia, according to George Washington University’s Program on Extremism. Counterprotester Heather Heyer was infamously killed at that rally when a madman plowed into her and several others. Members of the group were snapped riding the DC Metro Saturday. In one shot, a black woman sitting on the train...