World War II ended in victory parades. Korea ended in stalemate. The Vietnam War ended in controversy, neatly captured in 1971 by veteran John Kerry (now secretary of state) when he posed the rhetorical question: "How do you ask a man to be the last man to die for a mistake?"

The coming end of conventional combat operations in Afghanistan, after 13 years of fighting, doesn't resemble any of these models. Fought by an all-volunteer military, the war still draws young men who want to test themselves in combat, led...