Thousands of times over this decade of war, a service member has had to assume his dead boss's job, and those under him have had to adjust to new leadership during the most stressful time of their lives.
With the sharp bite of spent explosives still hanging in the air, Tom Whorl gripped the hand of his best friend, who lay dying in the sun-baked farmland of northern Marjah, his lower body torn open by a buried bomb. "It's going to be okay," he told him, yet knew it wouldn't.
The stricken Marine, Staff Sergeant James Malachowski was also his boss, and now Whorl had to assume his job: securing the area and calling in a medevac helicopter, then leading the men of 3rd Platoon, Fox Company, 2/8 Marines through the next several months of combat.
"So many people don't understand what it's like to be responsible for the lives of the Marines and Navy corpsman under me," Whorl wrote in his journal. "Every day is so stressful and I lose so much sleep worrying about the next day, planning and going over so much in my head, every move and decision calculated."
He was far from alone. Of the more than 6,600 troops killed in Iraq and Afghanistan, thousands have been in leadership positions: captains, colonels, sergeants. Which means that thousands of times over this decade of war, a service member has had to assume his dead boss's job, and those under him have had to adjust to new leadership during the most stressful time of their lives. Add to those the many thousands of leaders who have been grievously wounded and sent home, leaving more empty slots to fill.
It's a situation unfathomable to most in the civilian world, but one the military takes for granted. This is the timeless nature of armies and war: Soldiers die, and soldiers under them take their place.
Consider this: Of the 24 American service members who have died in Afghanistan since the beginning of October, at least 16 were in leadership positions. Or remember back to Iraq: During the most deadly month for Americans, November, 2004, leaders accounted for at least 72 of the 137 service members killed.
Some oversaw a platoon-worth of men or more, while a corporal or sergeant may have been in charge of just three other soldiers as a fire-team leader -- the position I held during two Iraq deployments -- but if that soldier falls, three others are left without a leader.
These aren't typical work relationships. Many of these leaders have met their subordinates' spouses and children. They've helped their younger soldiers through financial crisis and relationship woes, coached them on buying a new car and trained them for war. They know their blood types and how many pushups they can do.
And those taking over for them often don't get even a few hours to process what has happened and mentally prepare themselves for the new role; they take over amid the cries of the wounded and the crack of rifle fire.
The Army and the Marine Corps have done most of the bleeding and dying in Iraq and Afghanistan, and, within those two branches, most of the dead are infantrymen like Whorl, the frontline foot soldiers.
They learn from their earliest days of training that they are responsible for each other's lives, and must sacrifice without hesitation. "If a leader gets taken out, someone else takes over. That foundation is built from the very start," says Gunnery Sergeant Jeffrey Dean, a drill instructor at Parris Island, where Whorl and most of the men under him had gone through their basic training.
Leadership in war carries another weight: accepting the likelihood that some of those under you will be killed or wounded, no matter their preparation or the precautions taken.
A week before his boss died, Whorl lost the Marine directly under him, Corporal Ian Muller, the man he'd been grooming as his own replacement should he fall in battle.
The death crushed him, and that night he walked into the darkness outside his mud-walled patrol base and wept. But his men needed guidance and reassurance. They needed their leader. "You have to keep pushing," he told them the next morning before they departed for a foot patrol back to the same place their friend had been killed hours earlier. "You have to," he said, "because if you don't, then we've done nothing, we've accomplished nothing."
They nodded and filed out of the patrol base. Within an hour they were in yet another firefight, bellies pressed into the dirt as Taliban bullets sliced through the trees overhead.
Their war continued, in Afghanistan and then at home.
Whorl bore no physical wounds when he returned, but his burden was heavy, a savage mix of guilt over the fallen and an unrelenting feeling of responsibility for the living, who struggled with nightmares, rage and grief long after the deployment ended, a struggle shared with so many others, these veterans' of America's Long War, and every war before.