END OF AN ERA: The American tripwire dividing North and South Korea is no more.

PANMUNJOM, South Korea (Reuters) – The United States has relinquished its last outpost in the Demilitarized Zone to South Korea and cut troops there as part of a deal to give Seoul more responsibility for guarding the tense border with the North.

The change, which took effect at midnight on Sunday, is part of a much bigger picture in which the United States is cutting its forces on the divided peninsula by a third from 37,500 and moving bases further south away from the border.

South Koreans, especially those in the younger generation, increasingly resent the U.S. military presence. The war that purchased their freedom is passing out of living memory. I wish they could be a little more grateful. My grandfather was wounded in battle on their behalf. My father was stationed in the DMZ when I was born.

I can’t really blame them, though. South Korea isn’t a Third World victim anymore. It’s a grown-up First World success story now. Today marks their rite of passage into national adulthood.