On another Tuesday morning in September, 25 years after the attacks, President Trump spoke at the Ellipse in Washington, D.C., beside a battered steel beam lifted from the wreckage of the South Tower. Tunnel to Towers had carried the 16,000-pound piece of steel across the country. The gathering marked a quarter century since nearly 3,000 people were killed at the World Trade Center, the Pentagon, and on Flight 93.