Smith, Judge, McMahon, and Hickman were the final American combat fatalities in Korea, Vietnam, and Iraq, respectively. An unknown soldier will have the same fate in Afghanistan.

These men are the nation’s last full measure of devotion. The final casualty in war is uniquely poignant. It highlights the individual human price of conflict. It signifies the aggravated cruelty of near-survival. It has all the random arbitrariness of a lottery. The Soviet-made 122 mm rocket that killed Judge and McMahon in 1975 was famously inaccurate. It could have landed anywhere in their vicinity. But it fell just a few feet from the Marines. The sergeant who found their bodies wondered, “Why them and not me?”

Most of all, the final casualty underscores the value of ending a conflict. If the United States could have resolved the wars in Korea, Vietnam, and Iraq earlier—even just a few minutes earlier—Smith, Judge, McMahon, and Hickman’s lives would have been the first to be spared.

Concluding the fighting has particular urgency in a war without victory. As former navy lieutenant John Kerry remarked during congressional testimony on Vietnam in 1971, “How do you ask a man to be the last man to die for a mistake?”

Now, with ISIS seizing Palmyra in Syria and routing Iraqi security forces in Ramadi, an American victory in war once again seems an illusion. When the final U.S. soldier dies in Iraq—in one year’s time, in five years’ time, in 50 years’ time—Kerry’s question may still linger in the air.

* * *

Why does the United States struggle in war? How can it resolve a failing conflict? Can America return to victory?

Today, these are critical questions because we live in an age of unwinnable conflicts, where decisive triumph has proved to be a pipe dream.

On June 5, 1944, the day before D-Day, U.S. General George S. Patton strode onto a makeshift stage in southern England to address thousands of American soldiers. “Americans play to win all of the time,” said Patton. “That’s why Americans have never lost nor will ever lose a war, for the very idea of losing is hateful to an American.”

It was the golden age of American combat. Patton could look back on a century of U.S. victories in major wars against Mexico, the Confederacy, Spain, and Germany. And the glorious era was about to reach its pinnacle. “By God,” he said, looking ahead to D-Day, “I actually pity those poor sons of bitches we are going up against.” World War II was a testament to the valor-studded splendor of American warfare.

The price of military triumph was often immense. In the Civil War alone, there were around 750,000 American fatalities—more than the deaths in every other U.S. war combined. But if the costs of conflict were staggering, so were the benefits. The Civil War saved the Union and emancipated the slaves. World War II ensured the survival of liberal democracy in Western Europe. For Americans, golden-age conflicts became the model of what war ought to look like.