Sometime in 2012, or shortly thereafter, an American sergeant major in Seoul will haul down the flag of the four-star general who commands U.S. forces in South Korea. It will then be transferred to Fort Shafter in Hawai'i, where that general or his replacement will assume command of all U.S. Army forces in the Asia-Pacific region.

The shift of a top general will be among the final actions in a long, slow decline in the American engagement in Korea. Ten years ago, the U.S. had 36,000 soldiers, sailors, airmen, and marines in South Korea. A year ago, that was down to 24,700, with many anti-American Koreans cheering and urging that more Yankees go home.

But conservative political leaders and many senior Korean military officers, retired and serving, deplored the cutbacks and pleaded with the U.S. to maintain a larger contingent in Korea. The U.S. agreed to level up those forces at 28,500 by 2012.

Moreover, the U.S. will retain the mutual security with South Korea under which the U.S. is obligated to help defend South Korea. As evidence of that commitment, the U.S. has been lengthening the tours of troops posted in Korea and increasing the number of families accompanying those troops.

But senior U.S. officers have told the South Koreans they must be responsible for their own defense against communist North Korea, and the departure of the top U.S. general reflects that. Those officers have contended that South Korean forces are capable of deterring North Korea and, if deterrence fails, of repelling a North Korean attack, especially since Pyongyang's forces have been weakened by the rot in its economy.

Thus, in 2012, the U.S. will turn over to South Korea the wartime command of its own forces. Today, South Korea has peacetime command of its troops but wartime control remains with the U.S., a vestige of the Korean War of 1950-53 that the U.S. fought under the banner of the United Nations.

The mission of U.S. forces in Korea is changing. Where their primary task has been to help defend South Korea, those U.S. forces have become available to deploy elsewhere. They might rotate, for instance, to Afghanistan and return to Korea when that deployment was finished.

To prepare, the U.S. is building a new post in Pyongtaek and modernizing its airbase at nearby Osan, both 85 miles south of the demilitarized zone that divides the peninsula. U.S. forces will be consolidated, with about 26,000 of the 28,500 troops in Korea stationed in that complex.

From there, expeditions can be launched by air to wherever they are needed. What the U.S. armed forces call "full spectrum training," meaning everything from counter-insurgency to nuclear war, has already started. In the event of hostilities, American families could be quickly rounded up and evacuated.

Moving the four-star general from Seoul to Honolulu is part of a realignment of U.S. forces, including the command structure, in Asia and the Pacific. Having a four-star general in charge of U.S. Army, Pacific, or USARPAC, will put that officer on an even footing with the four-star officers commanding Navy and Air Force components of the Pacific Command, which has its headquarters here.

In addition, Pacific Command will have a top Army officer to deal with other armies in Asia and the Pacific. More and more, the Pacific Command's mission is to forge partnerships with other military forces for joint training and operations. In most Asian nations, the Army is the predominant service.

A three-star lieutenant general will take command of U.S. Forces Korea. A similar headquarters in Yokota controls U.S. forces in Japan. Both will report to the Pacific Command in Hawai'i.