On the morning of September 11, 2001, hijackers took control of four commercial airliners outbound from cities in the northeastern United States. They intentionally crashed two planes into the World Trade Center towers in New York City and one plane into the Pentagon building near Washington, D.C. The fourth plane, which was likely heading for the White House, crashed into a field in western Pennsylvania. Thousands were killed in the most devastating act of terrorism that had ever occurred on American soil.

Images of the attack were harrowing. Each of the collisions into the World Trade Center—and the ensuing fires and rescue efforts—were captured on film and broadcast around the world. Americans watched in shock and horror as the two 110-story buildings collapsed and as smoke from the wreckage enshrouded the lower Manhattan skyline. Three days later, Congress passed a resolution authorizing the use of...