Holding the Border.

Call them what you will. For decades GIs deployed along the demilitarized zone in South Korea were collectively known as a "tripwire" force--units whose main objective was to shed blood in the first moments of a North Korean attack, thereby committing the United States to the South's defense. But during a visit to the U.S. Army's Second Infantry Division (2ID) headquarters at Camp Red Cloud last week, Prime Minister Goh Kun christened their mission a "frontline partnership." His hastily coined phrase aims to quell U.S. anger over the tripwire characterization, which Gen. Leon J. LaPorte, commander of U.S. Forces Korea, recently called a "bankrupt concept."

The semantics betray deep strains in the Washington-Seoul alliance. This week, when South Korean President Roh Moo Hyun calls on George W. Bush for a get-to-know-you summit in the White House, talk will focus on the North Korean nuclear crisis. But the backdrop--indeed, the issue that overshadows all others in the 50-year-old partnership--is America's ongoing review of its role in the defense of South Korea. Officially, the Pentagon says its troops will stay as long as they're wanted and needed. But in the wake of 9-11, the huge anti-American protests that erupted across the South last year and America's recent blitzkrieg into Iraq, the Bush administration is questioning the utility of a force "whose mission it is to die or be wounded," says William Drennan, deputy director of the United States Institute of Peace in Washington. "People are asking: 'Do we really want to expose ourselves any longer?' "

Seoul may already know the answer. Just days after his election triumph last December, Roh tasked South Korea's top brass with making contingency plans for an eventual U.S. scale-down on the peninsula. They include a new command structure, a force reconfiguration and a procurement spree unprecedented since the cold war. While it's true that he has acted to slow any American departure, both by toning down anti-U.S. street protests and by arguing that it's unwise to pull GIs off the DMZ before the nuclear crisis abates, Roh's actions betray a belief that, sooner or later, Seoul will take a leading role in its own defense.

Washington isn't about to pull up its stakes and leave the Korean Peninsula entirely, to be sure. But serious discussions about downsizing the U.S. combat force in the South have been underway for months. In March the two sides began high-level negotiations on the alliance's future, and both promptly agreed to begin relocating the Eighth Army's Yongsan headquarters, a town-size complex located in the heart of Seoul, farther south later this year. Also in March, U.S. Defense Secretary Donald Rumsfeld said South Korea "has all the capability in the world of providing the kind of upfront deterrent that's needed" along the DMZ, adding that whether the 2ID would come home, move farther south or relocate to a neighboring ...