AdvertisementSept. 11 Legacy: One Endless War Against Many Radical EnemiesSeptember 06, 2016Greg MyrefacebookEmailU.S. Army soldiers take up a position during a patrol in Baghdad in 2007. The U.S. has been waging war nonstop for 15 years since the Sept. 11 attacks. Despite the protracted conflicts and disappointing results, U.S. involvement in multiple wars appears set to continue for years to come. (Getty Images)