We have looked into that question. Last month, in a visit to Seoul organized by the National Bureau of Asian Research and sponsored by the Korea Foundation, we spoke with scholars, journalists and officials from a number of Korean ministries. We found that military cooperation between South Korea and the United States is strong. But the politics of cooperation could be shaken up by unresolved differences or shocks.
U.S. and South Korean forces are deeply integrated
The U.S.-South Korea alliance has been formalized since the Korean War ended in 1953 in an armistice. The cornerstone of the military alliance is the Combined Forces Command (CFC), comprising equal numbers of U.S. and South Korean officers, designed to organize and plan the combined military effort against the North.
The CFC was founded in 1978. Before that, the U.S.-led United Nations Command (UNC) was responsible for defending South Korea. The bilateral CFC was created once South Korean forces recovered from the earlier conflict. As its capabilities continue to evolve, South Korea will eventually assume wartime operational control, called OPCON — although it will be years before South Korea meets the agreed-upon conditions for that transfer.
UNC still exists, primarily to monitor the armistice. So does U.S. Forces Korea, the U.S. military command that administers and supports U.S. forces on the Korean Peninsula. All three organizations are led by the same U.S. officer, currently Gen. Vincent Brooks.
The CFC’s structures and processes have built strong operational integration, enabling military decision-making that is faster and more efficient than if the United States and South Korea had two separate commands. Over decades of routine contact and work, this united operation has built habits and norms of cooperation.
In peacetime, the CFC plans, trains and otherwise prepares to defend South Korea. Operational planning teams are combined. U.S. and South Korean forces conduct several command post and field training exercises together each year to test and strengthen their ability to fight together. If conflict did erupt, the presidents of the United States and South Korea would assign control of their respective designated forces to the CFC. Individual combat units would remain separate U.S. or South Korean units, with a few exceptions. But they would be controlled by this deeply integrated command headquarters, under the command of a U.S. general.
There are some weak points. For instance, the United States plans to consolidate its forces by building two super-bases, one of which — the new Camp Humphreys base south of Seoul — will eventually contain the U.S. headquarters. That will separate some U.S. command and staff positions from their Korean counterparts still in Seoul — and may fray some of the cooperation nurtured over decades of being in proximity.
But political coordination fluctuates — a lot
Since President Trump’s inauguration, military structures have stayed just as closely integrated as before. That’s not true on the political front. Regular bilateral forums oversee the military alliance. Those include the annual Security Consultative Meeting between the U.S. defense secretary and the South Korean counterpart; the annual Military Committee Meeting between the U.S. and South Korean chairmen of the Joint Chiefs of Staff; and the semiannual Korean Integrated Defense Dialog between senior officials of the U.S. Defense Department and the South Korean Defense Ministry. These meetings collectively seek to coordinate defense policies and are regular and reliable. But the two sides’ policy approaches may not be.
The United States and South Korea nominally agree on a policy of “maximum pressure and engagement” — but clearly differ on the matter of emphasis. Trump asserts that Kim will respond only to pressure and has pressed with incendiary rhetoric and shows of military force. Last week at Camp David, Trump credited that pressure with bringing Kim to the table, claiming that “if I was not involved, they would not be talking Olympics right now.”
President Moon Jae-in of South Korea, on the other hand, believes Kim is primarily motivated by insecurity, and Moon argues that threats of force must be accompanied by diplomatic engagement. From 1998 to 2008, South Korean presidents followed a “Sunshine Policy,” which prioritized economic and diplomatic cooperation with the North, rather than threats of force. Similarly, Moon has consistently pledged to make diplomatic and development overtures to Pyongyang to bring the two countries closer — and has started doing so with the recent invitation to the Olympics. This is a departure from the approach of his immediate predecessor, Park Geun-hye, who, like Trump, preferred pressure to overtures.
Unsurprisingly, Seoul is much more reluctant to consider military force — and is especially wary of the prospect of unilateral U.S. military action. Moon has bluntly declared that no military strikes against the North — which Trump has repeatedly threatened — should take place until and unless South Korea agrees.
What does this all mean for the U.S.-South Korean alliance going forward?
In the second half of 2017, these different attitudes and policies caused trouble in the U.S.-South Korea alliance. South Korean observers we met were furious at the idea that the United States believes that South Korean deaths and casualties may be necessary to neutralize North Korea, as when, in August, Sen. Lindsey O. Graham (R-S.C.) said that Trump told him, “If there’s going to be a war to stop [Kim Jong Un], it will be over there. If thousands die, they’re going to die over there. They’re not going to die here. And he has told me that to my face.”
In other words, the military alliance is deeply integrated and reliable, which would make it highly effective in wartime. But there are few structures or standard operating procedures holding the two countries together politically. North Korea could indeed create a wedge between the United States and South Korea, reducing the alliance’s effectiveness in facing the North Korean nuclear threat.
Oriana Skylar Mastro (@osmastro) is an assistant professor of security studies at Georgetown University and a Jeanne Kirkpatrick Scholar at the American Enterprise Institute.
Arzan Tarapore (@arzandc) is a former analyst in the Australian Defense Department and recently completed a PhD in war studies at King’s College London.