The US is simultaneously challenging China, Iran, and Russia. Although war remains unlikely, all three involve potential military confrontations with significant powers.
Then there is North Korea. The "love affair" between the Norths Supreme Leader Kim Jong-un and President Donald Trump is long over, and Kim has refused to even get acquainted with President Joe Biden. Indeed, over the last two years the Democratic Peoples Republic of Korea turned sharply inward, suggesting that Kim may be returning to the autarkic policies of his father and grandfather.
However, Kim has not just sealed his people in. He continues to develop new weapons. Last week Pyongyang shot off another missile, short-range but supposedly hypersonic.
The DPRK already is a small nuclear power, with estimates of an arsenal with as many as 65 nuclear weapons. But that may just be the start. The Rand Corporation and Asan Institute warned:
"Despite some ROK and U.S. efforts to enhance defense and deterrence, there is a growing gap between the North Korean nuclear weapon threat and ROK and US capabilities to defeat it.
by 2027, North Korea could have 200 nuclear weapons and several dozen intercontinental ballistic missiles (ICBMs) and hundreds of theater missiles for delivering the nuclear weapons. The ROK and the United States are not prepared, and do not plan to be prepared, to deal with the coercive and warfighting leverage that these weapons would give North Korea."
With such a total the North would be a middling nuclear power alongside France, the United Kingdom, Israel, India, and Pakistan. The threat to the US still would be measured, since the DPRK would not possess a first-strike capability. Moreover, contra their image of Team America, North Koreas leaders have been shrewd operators, not undisciplined loons.
However, the ability to rain nukes upon South Korea, Japan, and American territories in the Pacific and, by then, likely the US homeland as well would provide the North with an effective deterrent to military action by Washington. That includes involvement in a conventional conflict on the Korean peninsula. Imagine war broke out, whatever the circumstance. A large influx of American forces would provide a convenient target for North Korean attacks. And any attempt to overrun the North, as the allies were poised to do in 1950 before Chinese intervention, would invite Kim to threaten nuclear strikes on the homeland if Washington did not pull back.
What in South Korea is worth the price of several US cities? Nothing.
Americas presence in Korea is an accident, resulting from the messy end of World War II. Japan surrendered on September 2, 1945. The peninsula was a Japanese colony. Washington proposed that the Soviet Union and US divide Korea into northern and southern occupation zones. The Cold War ended plans to reunite the two.
After establishment of both the Republic of Korea and DPRK, the US withdrew its forces. Washington did not view the peninsula as vital to American security but refused to provide Seoul with heavy weapons since President Syngman Rhee threatened to march north to forcibly reunify the peninsula. The Soviets were not so scrupulous about arming what became the DPRK, and in June 1950 the Norths Kim Il-sung invaded.
The Truman administration then reversed course and intervened. It had not changed its judgment regarding the Koreas intrinsic value, or lack thereof, but was concerned that failing to act might undermine European confidence and Soviet deterrence. As allied troops drove Kims forces northward, captured Pyongyang, and approached the Yalu river, the Peoples Republic of China intervened, creating what Gen. Douglas MacArthur termed "an entirely new war." Combat finally ended close to the original border, with an armistice concluded in July 1953.
At that time the ROK would not have survived without continuing US support, leading to the "Mutual" Defense Treaty (the Souths obligation was to agree to be defended) and a permanent "tripwire" troop presence. However, in the 1960s South Korea began to pull away from its northern neighbor economically. Democracy arrived in the late 1980s. Today the ROKs economy is among the worlds dozen largest, around 54 times that of the North. The South also has twice the DPRKs population.
Among the other South Korean advantages: a major industrial sector, vast technological edge, and much larger diplomatic network. ROK soft power permeates the globe and even the North, leading to frantic North Korean efforts to stamp out access to South Korean television, movies, and even K-pop. Evidently fearful of the corrosive impact of viewing a much wealthier, freer South, Kim also has begun emphasizing socialism at the expense of his heretofore godly father and grandfather. This may be a permanent reversal, aided by the isolation reinforced by the COVID-19 pandemic, with Kim determined to prevent ideological contamination by adopting autarky and (reluctantly) relying on China to ensure his regimes survival.
In any case, it is long past time for Seoul to take over responsibility for its own defense. The US no longer can afford to protect a gaggle of prosperous, populous allies around the world, including the ROK. South Koreans currently possess a qualitatively superior though numerically inferior conventional force. The North is capable of inflicting great destruction for instance, with artillery and missile attacks on Seoul, a mere 30 or so miles from the border but likely lacks the ability to win a full-scale war. The ROK could augment its military in any way necessary to deter the DPRK and defeat the latter in combat if necessary.
North Koreas possession of nuclear weapons admittedly adds a significant complication. The US could retain its so-called nuclear umbrella, but as the Norths capabilities increase an American promise to risk nuclear retaliation today at least on forces stationed throughout the Asia-Pacific, and eventually on the US homeland makes "extended deterrence" by the US ever less viable. In time the South would need to consider how to deter Pyongyang on its own. Making peace would avoid the problem but depends upon the DPRK. South Korea also could adopt forms of conventional deterrence, or even build its own nuclear weapons, a position long backed by the South Korean public. (Other US allies might eventually face a similar choice though they would not necessarily follow Seoul.)
Fans of the US-ROK alliance contend that it covers other forms of cooperation, but they could be maintained without an American promise to go to war on the Korean peninsula. Some Washington policymakers expect to use South Korean bases in any conflict with China, but Seoul wont even criticize the PRCs human rights record. The likelihood of the ROK agreeing to become a battlefield between the PRC and America, absent a direct Chinese attack on South Korea, is vanishingly small. Some observers worry about an American departure triggering an arms race in Asia, but that may be the best, and perhaps only, way to effectively deter Chinese adventurism. Anyway, rather than expecting the US to deter China, it would be far better for the nations directly threatened to build up their militaries for what is, after all, their defense.
Washington took on the role of GloboCop at the end of World War II. It was a unique moment in history. The case for America guaranteeing the security of countries around the globe had only temporary application. Years after economic recovery, national development, and political reform in Europe, South Korea, and Japan, the old arguments no longer apply. Given Americas challenges at home, political as well as economic, it is time for the US to start shifting rather than sharing burdens.
Korea would be a good place to start. Washington should inform the ROK of its intention to withdraw its troops and renegotiate the Mutual Defense Treaty, turning it into a genuinely "mutual" agreement providing for cooperation on issues of shared interest both in and out of Asia. The Korean people want to be treated as adults and equals. Washington should finally do so.