As the Army searches for answers in the Fort Hood massacre, one fact has become painfully obvious–Major Nidal Hasan, the military psychiatrist who killed 13 of his fellow soldiers and wounded 30 more–exhibited troubling behavior long before embarking on that murderous rampage.

But, as far as we can tell, no one in Hasan’s chain-of-command bothered to follow up on his vociferous opposition to the wars in Iraq and Afghanistan, and written comments that suicide bombers might be considered heroes–in the same vein as American soldiers who sacrifice their lives for those of their comrades.

According to various press accounts, Hasan entered the military in 1999, when he was accepted as a student at the Uniformed Services University of Health Sciences (USUHS), the only medical school in the armed forces. Entrance into the program required that Hasan be commissioned as a Second Lieutenant in a branch of the military (he chose the Army). One requirement for commissioning was a background check, required for his security clearance.

As part of that process, Hasan was required to fill out a Standard Form 86 (SF-86), the standard document used by all applicants seeking a clearance. For access to SECRET information (the clearance held by most military physicians), Hasan had to provide personal data for the previous five years, including addresses, schools attended and employers.

Information provided on that form was then checked against data in databases maintained by the FBI and local law enforcement. Inconsistencies between the SF-86 and the background checks would result in detailed questioning by the Defense Investigative Service. Failure to reconcile those issues would result in denial of a security clearance–and commissioning as a military officer.

To be fair, there probably wasn’t anything on the original SF-86 (or the background check) that would raise red flags with investigators. Hasan was a native-born American; the son of Palestinian emigres from Jordan. He attended three colleges in before finally graduating from Virginia Tech with a degree in biochemistry. A fairly standard resume for a medical student, although his peripatetic academic career might prompt a few questions, along with his age. Hasan was 29 when he entered the military medical school, a bit older than many of his classmates.

Still, in the days before 9-11, it was probably easy for Hasan to pass the required background checks, gain a security clearance, and admittance to the Hebert School of Medicine at the USUHS. And, with a 10-year window until the next update, Hasan’s questionable comments and behavior might not become a security issue until his clearance was up for renewal.

However, access to classified information can be denied long before the individual’s clearance comes up for review. Commanders can rescind a military member’s clearance for a variety of reasons, including questions about their allegiance to the United States, and perceptions of foreign influence and preference. Hasan’s comments and actions in recent years certainly fall into those categories.

Yet, there are no indications that Hasan’s superiors at Walter Reed or Fort Hood took any action to suspend or revoke his clearance. True, members of the Medical Corps don’t deal with classified material on a regular basis. But the alleged killer completed a fellowship in Disaster and Preventive Psychiatry and participated in at least one forum sponsored by the Department of Homeland Security. That raises new questions about Hasan’s potential access to classified data–and why a military doctor with a history of anti-American comments was selected for those programs.

Beyond security issues, there is also the troubling matter of why Hasan’s superiors never tried to discipline him for his conduct–or consider removing him from the military. NPR was among the few outlets to report that Major Hasan was suspended (briefly) during his tenure at Walter Reed, for proselytizing about his Muslim faith with colleagues and patients–many of whom were combat veterans from Iraq and Afghanistan, being treated for Post Traumatic Stress Disorder.

There are also accounts of Hasan engaging in heated debates with colleagues about the Global War on Terrorism, with the psychiatrist supporting anti-U.S. (and anti-military) positions. But that pattern of behavior–dating back several years–did not result in additional disciplinary action, or efforts to end his Army career. Despite his troubles at Walter Reed, Dr. Hasan was promoted to Major earlier this year.

His advancement is even more puzzling, given the fact that officers typically “pin on” their new rank about a 12-18 months after the promotion board meets. That means the panel that selected Hasan for advancement met in 2008, on the heels of his suspension at Walter Reed. Apparently, there wasn’t enough in Hasan’s personnel folder–including his performance reports–to prevent him from being promoted.

After completing his training (and being transferred to Fort Hood), Hasan’s troubling behavior and comments continued. A recently-retired Colonel–who worked with Hasan at the base mental health clinc–told the psychiatrist to “button it” on at least one occasion, after he launched into an anti-war tirade. But there is no indication that Dr. Hasan’s immediate supervisor, the hospital commander, or more senior officers at Fort Hood ever conducted a wider investigation into Hasan’s views, and their potential impact on post security.

We also know that the alleged killer appeared on the FBI’s radar earlier this year, after Hasan posted comments sympathetic to suicide bombers on a website. Because Hasan was an Army officer, there was almost certainly contact between FBI agents and senior officers at Fort Hood, not to mention the service’s Criminal Investigation Command. Yet, Dr. Hasan kept seeing patients at the post hospital.

The on-going investigation into the Fort Hood massacre will confirm what many of us already know; Army commanders either missed or ignored obvious warning signs, setting the stage for this week’s deadly rampage. But the larger question is why. We don’t want to prejudge any inquiry or report, but it’s a fair bet that authorities will blame poor coordination and communication between Hasan’s superiors at Walter Reed, and those at Fort Hood.

While there is probably an element of truth in that theory, it’s also clear that other elements were at play. First, the Army was anxious to recoup its significant investment in Hasan’s education and training. After nearly a decade in school, the service expected Dr. Hasan to fulfill his military obligations–and his debt to the taxpayer.

Secondly, the Army was in need of his services, despite Hasan’s spotty record as a mental health provider. With thousands of soldiers suffering from PTSD and other psychological disorders, the service needs all the psychiatrists, psychologists and counselors it can muster. We’re guessing there was pressure to keep Hasan on the job, so the busy Fort Hood clinic wouldn’t wind up being a “doctor short.”

Finally, there’s the ugly specter of political correctness as a factor in this equation. We’ve seen military commanders who are reluctant to punish minority military members, for fear of receiving discrimination complaints. Others buy into the “diversity celebration” business and are hesitant to remove a minority officer, lest they upset the demographic balance.

When we first heard about Hasan and his “record,” we thought back to some pearls of wisdom from Chief Buddy, one of the legendary “first shirts” and senior enlisted advisors in recent Air Force history. The Chief had absolutely no tolerance for sub-standard performers or individuals who couldn’t adapt to military life. JAGs at his various duty bases dreaded phone calls or visits from the chief, knowing that he was getting rid of another slacker, which meant more work for the legal folks.

But a senior JAG also paid him the ultimate compliment, saying “Chief, you never made a bad call.” Today’s military needs more leaders like that Chief Master Sergeant, individuals who are willing to make the tough decisions to preserve the integrity and yes, the security of our armed forces.

Nidal Hasan never belonged in the U.S. Army; his comments and actions in recent years only affirmed that suspicion. And, if someone at Walter Reed or Fort Hood had been willing to ignore expediency and make the tough (but correct) call, this week’s carnage could have been easily prevented.