"No Kings" marches in all 50 states were reminiscent of some of America's biggest debates, from Vietnam to civil rights.

President Donald Trump presided over a parade Saturday celebrating the nation’s military power and history, though the event was shadowed by political violence at home and escalating tensions abroad.Trump’s appearance on the reviewing stand south of the White House capped a harrowing day in which a Minnesota state lawmaker and her spouse were murdered — and another Democratic legislator and his wife wounded — in what authorities called a “politically motivated” attack.