(Past Tense): In the summer of 1969, the first U.S. troops were withdrawn from Vietnam. Their war was over, but mine was just beginning. The previous November, Richard Nixon had been elected president with a “secret plan” to end the war. Surely peace was near. That same month I received my draft notice. About 24,000 of the more than 58,000 Americans killed in Vietnam were yet to die. I didn’t want to be one of them. No one did.

I had demonstrated against the war from the safety of my college deferment, so I thought of going to Canada. I also thought of getting a friendly doctor to say I had bone spurs or anxiety, but those choices would mean someone else from my refinery-town high school would have to go in my place.

By the time I arrived in Vietnam a year later, the rate of troop withdrawals had increased. But in Paris the peace talks were proceeding at a glacial speed. Hundreds of Americans and thousands of Vietnamese had died while the diplomats argued about the shape of the table. I was flown out to a platoon in the foothills of the Truong Son mountains, near where the Ho Chi Minh Trail fed North Vietnamese troops and supplies into the northern provinces of South Vietnam. We circled a blasted hilltop still smoldering from enemy mortars. Gaunt, tanned Marines in ragged fatigues moved slowly as they went about their morning rituals, heating C-ration meals and welcoming security teams back from their night positions.

Here’s what I wrote in a letter home back then: “I have 58 men. Only 20 have high school diplomas. Average age 19. Over and over I read: address of father: unknown; education: one or two years of high school; occupation: laborer, pecan sheller, gas station attendant, Job Corps. They had grown up in the ghetto or Appalachia or along the Rio Grande border or on a rez. Kids with no place to go. No place but here.” They were expendable, and they knew it. I was the clueless 24-year-old 2nd Lt. who had been put in charge of them. They couldn’t care less that I had a fancy degree from Oxford. They didn’t want to know if I would help them win the war. They knew it was already lost. They were wondering, would I get them killed, or not?

At night we took two-hour watches, Hiers my radio man and the others in our command foxhole. On my watch a call came in from battalion headquarters. Da Nang had been hit by 122-mm rockets. We were ordered to cross the river to find and kill the rocket team. I had just arrived, so to me the attack on Da Nang was like the bombing of Pearl Harbor. I summoned my squad leaders and gave them the order. They laughed. No. Way. Not for a few relatively harmless rockets disturbing the comfortable sleep of the Americans in the rear. Besides, the enemy owned the night. Even during the day, a river crossing was one of the most dangerous maneuvers we could do. In the dark, we stood zero chance of finding the men who had fired the rockets but a serious chance of men being killed, wounded, lost or drowned. Solution: We would do the mission only on the radio, but no one would move a muscle. As far as battalion headquarters knew, we withdrew from our position, crossed the river and discovered no rocketeers on the other side. It was a virtual mission. At first light, we did it for real.

This was the Marines. These kids weren’t afraid of a fight. They would have stormed the beaches at Iwo Jima. They would have given their buddies the last drop of water and their last C-ration. They would go out under fire to bring a buddy back to safety. They would give their lives for one another. No hesitation. But would they give their lives for the diplomatic benefit of Nixon and Henry Kissinger? At the order of some hard-charging major safely back at base, who was making the most of a six-month combat posting to feather his résumé? We would die for one another, but we didn’t want to die for nothing.

In early 1970, the Pentagon announced that the 26th Marine Regiment would be withdrawn in April. That was us! Everyone wrote home with the good news. We were going to live! Then we learned about what was known as the “Mixmaster” strategy. All of the Marines throughout Vietnam who were already set to go home were transferred into our regiment. All of us who had been there for less time were transferred out. With great ceremony the 26th went home, but few of the men who went with it had ever actually served in the regiment. The rest of us were dispersed all over Vietnam; we went home on our regular rotation dates or in body bags. “Xin loi,” we said, “Tough break, don’t mean nothing.”

It’s been 50 years, which means Vietnam is as far from me today as World War I, another war of dubious purpose, was from me then. I remember so much. The lush shades of green. The smells of mud and water buffalo and human excrement and burned flesh. The blood and the leeches and the music playing from eight-tracks before the sun set and we all wondered if we would see it rise. The laughter, too. The smell of cordite and the sound of an enemy mortar being launched at us and the shells from the big 16-inch guns roaring over us like subway trains. I remember the helicopters and the green AK-47 tracer bullets coming at us, and the body bags and the orphanage children burned alive by the Viet Cong for having helped us. I remember the faces and the nicknames and the Freedom Bird calendars that marked the day we would fly out of this place, if it was the last thing we ever did. And for too many it was.

Whenever I stand at the Vietnam memorial, I see their faces looking back at me. I wonder what their lives might have been like, what they might have done for the world, what kind of fathers they might have been. And I think the same about the hundreds of thousands of Vietnamese who died on both sides, especially in those last six years after the peace talks began, when no one wanted to be the last to die for a lost cause.

I wished only that my own sons would not have to kill and die in such a senseless way. But after Sept. 11, my oldest son became a pararescueman, a Special Ops paramedic in the war we have been fighting for 18 years, as long as all of our 20-century wars combined. He was deployed to Iraq, Afghanistan, Djibouti, Uzbekistan and elsewhere. I alternated between great pride and helpless fury. I had cold sweats from thinking the car coming up the driveway was the casualty detail telling me that he had been killed. It was only then that I realized my own parents must have gone through the same thing.

We learn nothing.

This article originally appeared in The New York Times.