Documents from the Army’s inquiry indicate that the lead investigator, Maj. Gen. Kenneth Dahl, believed that the most serious charge Sergeant Bergdahl should face was desertion, carrying a sentence of up to five years. But Forces Command, under the command of Gen. Mark Milley, added a much more serious accusation: that Bergdahl had endangered the troops sent to search for him. The rarely used charge, formally known as misbehavior before the enemy, carries up to life in prison. Sergeant Bergdahl pleaded guilty to both charges.

General Dahl did not publicly reveal his investigative findings until September 2015, six months after the charges were filed. Sergeant Bergdahl had left his outpost with the misguided intention of hiking to a larger base so he could report concerns about problems in his unit, General Dahl said. The sergeant was delusional and naïve, but had never intended to defect to the Taliban.

In a victory for the defense, the preliminary hearing officer, Lt. Col. Mark Visger, said that while there was ample evidence to proceed to a court-martial on both charges, he endorsed General Dahl’s recommendation against jail time, saying the sergeant should be tried not at a general court-martial but before a lower tribunal where he would face only up to a year’s confinement.

There was also the question of Sergeant Bergdahl’s mental state. An Army medical board concluded that he had been suffering from a severe psychological disorder when he walked off his base. Two years before joining the Army, Sergeant Bergdahl had washed out of Coast Guard basic training for mental health and other reasons, and a Coast Guard physician said he should be cleared by a psychiatrist before being allowed to re-enlist in the military. But the Army apparently failed to obtain the clearance, Colonel Visger wrote.

“The fact that Sergeant Bergdahl had mental health problems was known within the U.S. military, and events may have transpired differently had concerns about Sergeant Bergdahl’s mental health been properly followed up,” he wrote.

The defense opted not to pursue a mental illness defense, but can still present evidence about his mental state during the sentencing phase of the trial in hopes of greater leniency.

Colonel Visger’s recommendation drew an immediate reaction. Senator John McCain of Arizona, the Republican chairman of the Armed Services Committee, which would sign off on any future promotions for the general overseeing the case, said publicly that Sergeant Bergdahl was “clearly a deserter,” and warned that the committee would hold hearings on the case if there was no punishment.