If the flags had been any more red, bulls would have come charging. Maj. Nidal Hasan was open about his radical Islamic beliefs. He tried to convert fellow doctors and patients. He was aggressive and argumentative. A defense investigator working with a terrorism task force in Washington discovered e-mails Hasan sent to a radical cleric in Yemen. There were complaints about his erratic, troubling behavior.

So what was the official response? The Washington Post quoted a staff member at the Walter Reed Army Medical Center as saying supervisors ordered Hasan to attend lectures on Islam, the Middle East and terrorism.

A lot of second-guessing has been swirling through the air since Hasan allegedly opened fire at Fort Hood in Texas last week, killing 13 and injuring dozens more. At its worst, the tragedy has been twisted by some on the right as evidence that all Muslims should be treated with suspicion, and by some on the left as nothing more than the result of some sort of trauma Hasan suffered as a result of listening to patients describe their traumatic war experiences. Both theories are baloney.

Hasan's past behavior, and his alleged screams of "Allahu Akbar!" as he began his murderous rampage may indeed be evidence that he had adopted the dangerous political ideology of Islamic terrorists — perhaps a devout Muslim would call them "heretics" — with whom the United States is at war. Military investigators cannot let political correctness stand in the way of their honest appraisal of the facts.

More importantly, however, the military cannot afford to allow political correctness to keep officers and other supervisors from taking preemptive steps when one of their own begins to show signs not only of sympathizing, but of actively supporting the enemy.

Tolerance is no virtue when it provides safe refuge for such people. Nor should the fear of offending someone's religious beliefs stand in the way of seriously investigating warning signs.

America's public schools reacted to the Columbine tragedy by training teachers to identify possibly dangerous warning signs. The result has been to preempt many potential tragedies. Although this isn't a foolproof system, it has put teachers and administrators on alert, which in turn has made schools safer.

Perhaps Fort Hood will serve as the same sort of catalyst to make the military more alert to warning signs. If so, the tragedy is that it cost so many lives to make the nation's defenders more vigilant about defending themselves.