In a speech on Tuesday, President Biden identified his decision to withdraw from Afghanistan with his desire to end the “forever war.” But he also promised that America will “maintain the fight against terrorism in Afghanistan and in other countries.” The reality today, he said, is that “we don’t need to fight a ground war to do it.”

In this, Mr. Biden’s speech made explicit what was already obvious. With the last American troops now out of the country, it is clearer what America’s bequest to the world has been over the past 20 years: a disturbing new form of counterterrorist belligerency, at once endless and humane. This has transformed American traditions of warmaking, and the withdrawal from Afghanistan is, in fact, a final step in the transformation.

The desire to fight more-humane war would not have made sense to prior generations of Americans. Originating in constant and pitiless wars against Native people, American fighting was brutal even before it went abroad. Similar violence was later extended against Filipinos in the country’s first overseas imperial counterinsurgency. Air war only intensified American traditions of brutality, and in World War II, the Korean War and Vietnam, few limits were respected, either in principle or practice. Asian foes were regularly compared to Native Americans — and were legitimate targets of the same violence — by commentators and soldiers.

Those traditions hardly evaporated after Sept. 11, 2001. The Middle East was sometimes treated as a new frontier; Osama bin Laden was reportedly code-named Geronimo by the forces who killed him in 2011. But by that point American culture was already giving rise to a newer tradition — one that continues to characterize the war on terror.

The groundwork was laid after the Vietnam War, which had left many Americans ashamed of their country’s overseas violence. At the same time, global activism pushed to make the laws of war, either ignored or permissive before, more humane in content and honored in practice. In the 1970s, for the first time, the obligation not to target civilians — especially in aerial bombardment — was put on paper, along with a new requirement to strike only when the expected military advantage outweighed collateral damage.