Just a little more than 53 years ago, President Truman sent American troops to fight in a land few of them had heard of before -- and for a people they didn't know. The Korean War, often called the "forgotten conflict" except by those who fought it, ended in an armistice 50 years ago yesterday.

More than 40,000 Americans lost their lives or went missing; another 92,000 GIs were wounded; and more than a million and a half Koreans perished in what the U.N. called a "police action." It was not a police action by any stretch of the imagination; it was war.

If you can believe it, absent a final peace treaty, technically the two Koreas are still at war. (More accurately, the U.N. and North Korea are still at war.) And unless you've seen the latest James Bond flick, "Die Another Day," a quick visit to the oxymoronic demilitarized zone (the infamous 38th parallel), which divides the two Koreas, will quickly convince you that the Korean peninsula is one of the most dangerous places on earth.

And for good reason: North Korea has the world's fourth-largest army, including 1.2 million soldiers, chemical and biological weapons and 10,000 artillery pieces that can reach Seoul, the South Korean capital 25 miles south of the DMZ. Sixty percent of North Korea's People's Army is spring-loaded for action within 70 miles of the dividing line.

On the other side of the border, 650,000 South Korean troops and 37,000 American servicemen and women stand guard against North Korean aggression. The unofficial motto of U.S. Forces Korea is: "Ready to fight tonight." And ready to fight at a moment's notice they must be, considering they would be among the first to counter a communist North Korean onslaught.

Just to make sure things don't get boring on the last frontier of the Cold War, North Korea is pursuing a nuclear weapons program. Pyongyang is also developing intercontinental ballistic missiles capable of reaching the American mainland -- and mated with nuclear warheads, of course.

(Fortunately, President Bush has had the wisdom to move ahead with missile defense.)

To further complicate matters, there has been an up-tick in anti-Americanism in South Korea, most notably during last December's presidential elections there. Some South Koreans have called for U.S. forces to withdraw from the peninsula.

Although these sentiments are probably not part of mainstream Korean society, many Americans, rightfully so, have taken offense and echoed the Koreans' call for a withdrawal of American troops. This is not a good idea.

Despite the burden of maintaining peace on the Korean peninsula for more than 50 years, the work isn't done yet. And an American withdrawal would do more harm than good, both to American and South Korean national interests and to regional stability.

For example: The likelihood of another conflict between North and South Korea is vastly increased by a U.S. withdrawal. After an initial occupation of the southern portion of the peninsula after World War II, American forces left South Korea in June 1949. Just one year later, absent a U.S. presence and a firm security commitment from Washington, North Korea invaded with devastating effects. U.S. forces are required in South Korea to deter future North Korean belligerence.

Thankfully, President Bush and South Korea's President Roh recognize the importance of the American presence as well and intend to make sure the alliance is ready for the 21st century.

The dramatic changes in warfare and technology provide opportunities to strengthen the U.S.-South Korean alliance. New capabilities in long-range, high-precision munitions, intelligence and information systems, and joint operations demonstrated in Afghanistan and Iraq should be incorporated into the defense of South Korea. It also seems appropriate to look at defense cost- and burden-sharing (Korea should do more on both accounts) and the location of U.S. forces on the peninsula in light of these new capabilities.

The U.S. will, of course, do its part to enhance the partnership. According to the Pentagon, Washington will make an $11 billion investment in some 150 military capabilities over the next four years that will enhance American war-fighting on the peninsula, including Patriot PAC-3 surface-to-air missiles (of Gulf War I/II fame), the Army's new, highly mobile Stryker brigade and the Navy's High Speed Vessel.

The U.S.-South Korean alliance is a partnership forged in time, blood and valor. It is strengthened by the shared common values of freedom, democracy and open markets and by the millions of Koreans who have come to America's shores as immigrants. It is appropriate for Seoul and Washington to upgrade their defense relationship to ensure that it is capable of meeting the increasing security challenges posed by Pyongyang.

As Yogi Berra said, "It ain't over till it's over."

And American forces should be there until it's over -- once and for all.