American soldiers have turned their guns on their comrades before. Yet Thursday's horrific shooting rampage at Fort Hood, Texas -- a burst of furious bloodletting apparently inflicted by a single deranged soldier -- is the worst in memory. The shooter, identified by the Army as Maj. Nidal Malik Hasan, a 39-year-old Army psychiatrist, took 12 lives and wounded 31 others, some critically. An intensive, multi-agency investigation led by the Army was immediately begun to determine any possible motives of the gunman, but in the interim Americans are left to wonder in sadness just why this tragedy occurred and how it possibly could have been averted.

Though shot several times by military police, Maj. Hasan reportedly was in stable condition Friday. His story has yet to come out. A cousin interviewed by The New York Times, Nader Hasan, a lawyer in northern Virginia, gave an abbreviated history. Maj. Hasan, he said, is an unmarried, American-born son of immigrants. He reportedly was never religiously oriented, but after his parents died became more religious.

He had joined the Army, the cousin said, as a matter of national duty and against his parents wishes. Through the Army, he became a doctor and did his residency at Walter Reed Medical Center, where he counseled many severely wounded soldiers before being transferred to the Darnell Army Medical Center at Fort Hood, the nation's largest military post, earlier this year.

Nader Hasan told the New York Times that his cousin was due to be deployed to Iraq or Afghanistan soon and was mortified about that prospect because of the many horror stories he had heard at Walter Reed. He had employed a lawyer to see if he could leave the Army before his commitment was completed, but reportedly was told that wasn't possible and had quit trying to get out of the Army. His cousin also said Maj. Hasan had become upset about being castigated as a Muslim in the aftermath of the 9/11 terrorist strikes.

That history alone is insufficient grounds on which to make a judgment, but it does suggest a man isolated and in turmoil. It also may prompt Americans to assume religious motivations for his alleged attack, rather than a more general psychiatric or emotional disorder. That would be unwarranted.

The national Council on American-Islamic Relations issued a statement Thursday pointing that while a motive has not been determined, CAIR and the American Muslim community condemned the cowardly attack. CAIR rightly wants to distance America's Muslim community from the connection that some may draw between Maj. Hasan and an empathy for extremist Muslims elsewhere in the world

"No political or religious ideology could ever justify or excuse such wanton and indiscriminate violence," CAIR said. It described the violence as "particularly heinous in that it targeted our nation's all-volunteer army that includes thousands of Muslims in all services." CAIR also offered its "thoughts and prayers for the victims and sincere condolences for the families of those killed and injured."

Other threads of the tragedy also raise questions. The shooting occurred at a processing center for arriving and departing soldiers. Maj. Hasan allegedly used two handguns, neither a service weapon, in his shooting spree. His ability to carry weapons into the center must be reviewed.

Though Fort Hood is one the Army's busiest posts for soldiers departing to or returning from the war zones, soldiers in the sprawling 340-square miles base -- a virtual city of more than 50,000 soldiers and another 150,000 families members and civilian workers -- are not allowed to randomly carry guns. Weapons are restricted to appropriate training areas, and only the military police are authorized to carry weapons in most areas. That raises a question of enforcement of gun controls at the base.

Lastly, there's a question about how the Army copes with soldiers who at some point find themselves retreating from the emotional stress of warfare after they have made a commitment to serve and received expensive training. Traditional wisdom is that soldiers typically brave the horror of war not for lack of fear, but for bonds to their friends and comrades. But where is the line between enforcing discipline and making them serve, as opposed to allowing them an out before they blow up? In a all-volunteer service, that's a question that begs more consideration.