In the deadliest assault on a military base in the U.S. in history, Major Nidal Malik Hasan rampaged through Fort Hood in Texas on Nov. 5, killing 13 people — including 12 troops — and wounding more than 30. An Army psychiatrist charged with caring for soldiers scarred by a war he was scared to join, Hasan was cast by some as a shattered loner driven to madness by the prospect of fighting against fellow Muslims in Afghanistan. Others feared that he was a harbinger of the future of terrorism: single-person cells activated by little else than virtual adherence to an extremist creed headquartered in a cave. But as critics noted, before Hasan snapped, he hoisted a series of warning signs, including a PowerPoint deck castigating U.S. foreign policy, Internet posts glorifying suicide bombers and e-mail exchanges with a radical Yemeni cleric. Critics have suggested that Army officials failed to respond to the barrage of red flags because they feared accusations of racial profiling.