After Sgt. Bowe Bergdahl recovers physically and mentally, he'll face a host of questions about his disappearance.
Credit: U.S. Army

As controversy grows over the exchange of five Taliban insurgents for the captured American soldier Bowe Bergdahl, some have argued that the Army sergeant deserted his platoon.

Nobody but Bergdahl himself can accurately assess the soldier's motives for leaving his base in Afghanistan, but the situation raises a question: What could make someone desert their squad, especially in a war zone?

Soldiers typically abandon their posts for complicated personal reasons, such as financial woes, family troubles, or difficulty adjusting to military life, according to the U.S. military. Relatively few leave because they object to the war, and cases involving those who cross battle lines to join their enemies are even more unusual, they say.

Unit cohesion

Soldiers can be punished for being absent without leave (AWOL), but true desertion requires an intention to shirk military duty and not return. Desertion is perceived as a grave threat to a military unit's health, said Eric Zillmer, a neuropsychologist at Drexel University in Philadelphia, and the author of "Military Psychology" (The Guilford Press, 2012). [What is Desertion]

"The whole system of the armed forces is based on obedience, loyalty, backing people up," Zillmer told Live Science. Desertion "really undermines the whole vertical hierarchy of the military."

Many soldiers reported as AWOL simply got blitzed at the bar and overslept, or lingered an extra day on leave, with full intentions of returning to their base. Few intentionally shirk their duty permanently, Zillmer said.

Difficult prediction

In the early 20th century, the military conducted several studies to pinpoint those individuals likely to desert. Yet, none could accurately predict who would wither or shine in military life.

(The military does use assessments to weed out those who are thought to be unfit for duty, typically because of mental health issues such as anxiety or problems with impulsiveness, Zillmer said.)

Those who go AWOL or desert tend to come from lower socioeconomic backgrounds, have a lower aptitude and a history of delinquency before entering the armed services, according to a 2002 study by the U.S. Army Research Institute for the Behavioral and Social Sciences. They also tend to be junior officers who have been in the military for less than a year, according to an Army spokesman.

However, trying to intervene makes the problem worse, probably because those pegged as "at risk" for desertion felt they were being scapegoated and singled out as troublemakers, the 2002 study found.

Shell shock to disaffection

The reasons for abandoning a post may vary depending on the war, research has shown. Sometimes, people simply can't take any more.

In World War II, for instance, "most of the British and American deserters, the overwhelming majority were frontline combat soldiers who, for the most part left the lines because they'd had nervous breakdowns," said Charles Glass, the author of "The Deserters: A Hidden History of World War II," (Penguin Press HC, 2013). "Too much shelling, close friends killed, not getting any sleep — the daily stresses were too much."

During the Vietnam War, many went AWOL, checked out on drugs, or simply wouldn't go on patrol because they had lost faith in the cause, said Robert Musil, the president of the Rachel Carson Council and an executive director of CCCO: An Agency for Military and Draft Counseling.

Muddled mix

In more recent conflicts, those who leave their posts often say the decision had been brewing for a while, and their motivation is a muddled mix of personal or financial reasons, dislike of military life, and disaffection with justifications for the wars, Musil told Live Science.

Some simply hate military life, said Stephen Karns, a military lawyer who has defended soldiers against desertion charges.

"You get people who say, 'This is not what I signed up for, I was misled,'" Karns told Live Science.

In particular, those labeled "weaklings" may be viciously hazed or bullied. Given that the commanding officer who would ordinarily handle complaints may be the same person making their life miserable, there's often little recourse for these people, Karns said.

They may also have trouble articulating why they are a poor fit for military life, or lack the savvy to pursue more formal alternatives, such as administrative leave or conscientious objector status, Musil said.

Unknowable

The public may never find out what Bowe Bergdahl was thinking when he left his post. Most abandon posts on American soil or while in a peaceful country, making it easy to return to family or forge a new life, Zillmer said.

This is why Bergdahl's decision to leave in a war zone with no public transportation infrastructure is even more mystifying, Zillmer said.

Bergdahl left his post in Afghanistan once before and sneaked away from his training camp in California, either to see a sunrise or sunset, or simply to see how far he could go, according to a 2009 classified military report, The New York Times reported.

So it may be that he was simply an odd duck, who didn't think his decision through before he took it, Karns said.

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