WASHINGTON—President Donald Trump spoke before an estimated 150,000 people gathered at the National Mall on the evening of the Fourth of July to celebrate the 250th anniversary of the United States of America. “We’re celebrating freedom’s triumph over tyranny, liberty’s conquest over oppression, and the enduring victory of the American spirit—from July 4, 1776, to July 4, 2026,” the president said. Trump said that an estimated 375,000 people had gathered for the Salute to America 250 celebration event before organizers issued an evacuation order at around 7 p.m. ahead of a gathering thunderstorm. Many spectators were unable to return for the celebration due to the delays....