After terrorists took control of four airliners on Sept. 11, 2001—destroying the World Trade Center’s twin towers, flying into the Pentagon and crashing into a Pennsylvania field—it became commonplace to say, “9/11 changed everything.”
It was difficult not to believe this was true. The shock of that day was deep. Nothing like this—nearly 3,000 Americans murdered in a few hours—had happened on U.S. soil despite two world wars. America was immune from militarized invasions. Now we weren’t.
