Hasan "should have been gone," says Joe Lieberman, chair of the Senate Committee on Homeland Security.

Lieberman promises to ask the hard questions about why Nidal Malik Hasan was tolerated despite warning signs. And let no one be in denial: The warning signs were beyond clear.

Major Nidal Malik Hasan, the gunman who killed 13 at America's Fort Hood military base, once gave a lecture to other doctors in which he said non-believers should be beheaded and have boiling oil poured down their throats.

He also told colleagues at America's top military hospital that non-Muslims were infidels condemned to hell who should be set on fire. The outburst came during an hour-long talk Hasan, an Army psychiatrist, gave on the Koran in front of dozens of other doctors at Walter Reed Army Medical Centre in Washington DC, where he worked for six years before arriving at Fort Hood in July.

Colleagues had expected a discussion on a medical issue but were instead given an extremist interpretation of the Koran, which Hasan appeared to believe....

Fellow doctors have recounted how they were repeatedly harangued by Hasan about religion and that he openly claimed to be a "Muslim first and American second."

One Army doctor who knew him said a fear of appearing discriminatory against a Muslim soldier had stopped fellow officers from filing formal complaints.

Another, Dr Val Finnell, who took a course with him in 2007 at the Uniformed Services University of the Health Sciences in Maryland, did complain about Hasan's "anti-American rants." He said: "The system is not doing what it's supposed to do. He at least should have been confronted about these beliefs, told to cease and desist, and to shape up or ship out. I really questioned his loyalty."

It is pathetic not to be able to distinguish between discrimination again Muslims and seeing that something is wrong with a particular individual who is a Muslim. It is thoroughly inept to think you have to choose between fighting terrorism and avoiding invidious discrimination.

It would seem that the Army was vulnerable to Rule 4 of Saul Alinsky's "Rules for Radicals":

Make the enemy live up to its own book of rules. You can kill them with this, for they can no more obey their own rules than the Christian Church can live up to Christianity.

Of course, we should live up to our own rules. The key is to have good rules and not to distort your own rules out of fear of erring in one direction when there are multiple interests at stake. I imagine that Hasan thought his colleagues were complete idiots to let him get away with the outrageous things that he — a psychiatrist! — said.