WASHINGTON - In a country where mass killings have sadly become routine, Americans are particularly traumatized by the alleged crimes of an Army psychiatrist who had apparently asked for a discharge before going on a pre-deployment shooting spree on a Texas military base.

The debate about Nidal Malik Hasan, the only suspect in the shootings at Fort Hood that left 13 people dead and dozens wounded, has been split down firmly entrenched political fault lines, as is usually the case in the United States.

The right is pointing to the devout Muslim's ethnic background and religious beliefs, and suspect the major's alleged shooting spree was another terrorist attack on America by an Islamic extremist. The left, meantime, is blaming the trauma of two wildly unpopular wars being waged by the United States in the Middle East.

Hasan's relatives say he was stricken by the stories he heard while counselling soldiers who'd returned from Iraq. They say he was bullied for being a Muslim after the 9-11 terrorist attacks and wanted to leave the Army. Hasan was also angry, they say, that President Barack Obama was not pulling U.S. troops out of Iraq and Afghanistan.

Messages posted under Hasan's name defending suicide bombers had been under investigation. His superiors were concerned about his conduct with patients. A Texas congressman said authorities have told him Hasan had recently taken weapons classes, unusual for an Army psychiatrist.

Those revelations were raising questions Friday about the U.S. Army's screening procedures.

The military has struggled for years to recruit enough soldiers to fight in Iraq and Afghanistan, with no uptick in volunteers until the economic recession took hold last year. And there have been concerns for the past four years about lowering standards for military personnel.

"We warned the military about this," Paul Sullivan, executive director of Veterans for Common Sense, said in the aftermath of the shootings at Fort Hood.

"We warned the military about the need to increase the number of mental health care providers. We warned the military about lowering recruiting standards ... we have been working tirelessly to prevent this from happening."

Robert Gibbs, the White House press secretary, dodged questions Friday about whether military officials missed ominous warning signs about Hasan.

"We are right now focused, with the Department of Defense and the FBI, on what happened. And this will be thoroughly reviewed," Gibbs said at the daily press briefing at the White House.

Tom Kenniff, an Army officer, member of the Judge Advocate General's Corps and Iraq war veteran who once served in the Iraqi town of Tikrit, said he was suspicious of the story emanating from Hasan's relatives.

In a live chat on the Washington Post website, Kenniff said it would be highly unusual for the Army to tolerate any bigoted harassment of a much-coveted military doctor with a high ranking. Army officials say there's no record of any complaints from Hasan about such harassment.

Kenniff also speculated Hasan hadn't, in fact, made a formal request to be discharged and had likely signed another contract with the Army in the past couple of years.

"He voluntarily entered the Army and availed himself of the benefits, probably at least twice," Kenniff said.

"The reality is if he truly didn't want to deploy, as a major and a doctor, he probably could have wiggled his way out of it. He could have claimed 'conscientious objector' or sought stateside duty. Believe me, the Army is not looking to send someone of Islamic faith to a combat zone when they're protesting the war."

The U.S. Army also puts personnel through a painstaking screening process before deployment, Kenniff said - and they should have picked up on some of the revelations about his conduct and beliefs now coming to light.

"The military conducts extensive background/security checks on both enlisted and officers. If he was going to be deployed, he would have had to be screened for a security clearance ... (I) don't know how they would have missed this, but it's very scary."

Just as they do in Canada, anyone joining the U.S. Army enters into a contract to serve that can vary in length. North of the border, a Canadian military official said Friday, there's an extensive interview process with soldiers just before deployment to determine whether they're emotionally fit for their tour of duty.

It's unclear whether that happened with Hasan stateside. A military official told The Associated Press that Hasan had indicated he didn't want to go to Iraq, but was willing to serve in Afghanistan.

"It's going to be very interesting to see what comes out during Hasan's trial in terms of military procedures," said the Canadian Army official. "This is going to dig up all sorts of fascinating information in the next year or two."

Hasan's Palestinian heritage and Islamic faith have touched a nerve, serving as painful reminders of what prompted the wars in Iraq and Afghanistan to begin with - the terrorist attacks of Sept. 11, 2001, carried out by Muslim extremists.

Congressman Michael McCaul said Friday that military officials told him they hoped to interview Hasan to determine whether he was working with foreign agents.

"From an intelligence standpoint, that's key, finding out if he talked to anyone overseas," McCaul said.

Meanwhile, it's no secret that being a soldier in the United States can push people to the breaking point.

The U.S. Army has been dealing for years with a rising number of stress-related homicides and suicides among soldiers who are serving in Iraq and Afghanistan, or have returned from combat in those conflicts. Many troops are on their third or fourth tour of duty.

Some studies have suggested that about 15 per cent of soldiers returning from Iraq suffer from emotional problems. Last year, there were 128 confirmed suicides by U.S. Army personnel, and 41 by Marines. Those are the highest numbers since officials began keeping records in 1980.

Yet the recession and weak job market have enticed more Americans into a military career in recent months. The Pentagon says recruitment levels were met for the first time last year since 1973, when the military became an all-volunteer force.

The Iraq war began to eat into recruitment levels in 2005, when the Army missed its goal for the number of recruits. In 2007, for the third year in a row, the Army did not meet its benchmark for the level of educational attainment of recruits, and the percentage of recruits the Department of Defense considered 'high quality' had also dropped considerably.

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