In June of 2011, Isaac Aguigui and his wife, Deirdre, learned that they were going to have a boy. Aguigui, then twenty years old and a private in the Army, spoke excitedly with friends about becoming a parent. Deirdre, twenty-three and a sergeant, sent her father a text announcing, "It's a boy," repeating the final word eight times to punctuate her glee. They picked out a name, Kalvin James, and when Deirdre adopted an orange tabby they named it Hobbes, evoking the comic strip "Calvin and Hobbes."

The two had met in 2009, as cadet candidates at the U.S. Military Academy Preparatory School for West Point, at Fort Monmouth, New Jersey. Deirdre tutored Aguigui in math; he was gregarious and handsome, with black hair and angular features. "She was elated she'd found the right guy," her father, Alma Wetzker, said. When Wetzker met Aguigui, he was charmed. "I sensed a kindred spirit who thought a lot like me," he said. The relationship wasn't against the school's rules, but it was contrary to its spirit of discipline: barracks are gender-segregated, and cadets must be single. After Aguigui's roommate accused him of sleeping with Deirdre in his bed, they quarrelled, and Aguigui was kicked out. Rather than give up on military life, he enlisted in the Army. Deirdre, who had enlisted a few years earlier, dropped out of school to marry him.

Aguigui went to basic training, and then to Fort Huachuca, Arizona, for advanced instruction in military intelligence; Deirdre deployed to Iraq. When she returned, in December of 2010, the couple moved into a two-bedroom apartment on base at Fort Stewart, Georgia. Distance had frayed their relationship, and proximity didn't seem to help much, either. Still, their prospects had improved by the summer of 2011. Deirdre had been promoted to sergeant, four ranks above her husband. And Kalvin, conceived during a period of reconciliation, seemed to signal happier times. Deirdre turned their second bedroom into a nursery, buying a mahogany crib and a high chair. On July 4th, the couple went to a concert by the Zac Brown Band, a country group, and Deirdre called her husband's childhood friend Matthew Asimakoupoulos. "She was telling me how good she and Isaac were doing," he recalled. "They were getting back together. She sounded happy."

In July, when Deirdre was five months pregnant, she complained on Facebook of terrible heartburn. "I feel like I swallowed a fire ball," she wrote. A few days later, her parents got a phone call from Aguigui. "He said he went to lie down and Deirdre went to watch TV in the other room," Wetzker recalled. "When Isaac got up, Deirdre was unresponsive. He tried to wake her up and rushed her to the E.R. They worked on her for about an hour and tried to save the baby, but it didn't work." Aguigui told another soldier that doctors believed a blood clot had killed Deirdre; she had suffered an embolism in Iraq. But, in an audio diary that he kept, he made an entry three months later in which he blamed himself. "I'm feeling lonely, sad, confused, angry, frustrated, pissed at the world, pissed at myself," he said. "I keep thinking about the night she died and I get angry that I didn't know C.P.R. What kind of fucking soldier doesn't know C.P.R.?"

At Deirdre's funeral, Aguigui was withdrawn, avoiding her parents. "You could tell he was devastated," Asimakoupoulos said. "He didn't want to be around people. I think he was trying to cope with it in his head and get through it." But grief didn't prevent Aguigui from visiting the Army office in charge of death benefits two days after Deirdre's death. As the spouse of a soldier who died on active duty, he was entitled to about half a million dollars. Within days, he got an initial payment of a hundred thousand.

Fort Stewart, in southeast Georgia, is the home of the 3rd Infantry Division, which led the invasion of Iraq, in 2003. It is the largest military installation in the East, more than three times the size of Atlanta. Separated from the neighboring town of Hinesville by security checkpoints, it combines suburban living and Army discipline; inside the gates are low-slung brick buildings that wouldn't be out of place in a strip mall, set off by grassy fields, a Burger King, a commissary store. Aguigui belonged to a squadron of five hundred soldiers, of whom about eighty were stationed at Fort Stewart—the rear guard for the soldiers who had deployed to Mosul, Iraq. On the base, new privates mingled with soldiers returning from difficult tours of duty.

After Deirdre's death, Aguigui was relegated to the barracks for single soldiers, known as a center for drinking and easy hookups. He threw a keg party and broke down in tears in the middle of it. He went to the Temptations strip club, across the border in South Carolina, and the higher-end Platinum Plus. He ended up dating two strippers, and, they later said, gave them thousands of dollars to help pay bills. At after-parties with the strippers, he smoked a synthetic marijuana called Spice; he snorted bath salts and cocaine and took Ecstasy. As Aguigui's friend and fellow-soldier Sergeant Michael Schaefer told me, from a jail in Columbia, where he was serving time for robbery, "He started going crazy."

Aguigui became close to Private Christopher Salmon, nicknamed Phish, who had been caught committing travel-voucher fraud in Iraq and was assigned extra duty as punishment. His wife, Heather, was pregnant, and she had recently been discharged from the Army for prescription-drug abuse. The two men sat together, smoking Spice and talking about their deepening antipathy toward the military and the government. At first, Heather was skeptical of Aguigui; she had met him before Deirdre died, at a beer-pong party off post, and overheard him arranging to meet a girl at the barracks. But after Deirdre's death she felt sorry for him—and, she said, "he was my husband's best friend." She suggested inviting him to dinner at their home, a white four-bedroom row house on the base. "He came to my house and never really left," she said. "One night turned into a week, a week turned into a month." He took over the couch, and then moved into his own room.