By Kyle Ferrier

It may have just been bravado to further his image as a tough negotiator, but President Trump’s comments suggesting that the withdrawal of U.S. troops on the Korean Peninsula may be on the table is problematic to say the least. Leaked comments from a private fundraiser on Wednesday revealed the president stated, “We have a very big trade deficit with [South Korea], and we protect them.” He further went on to say, “We lose money on trade, and we lose money on the military. We have right now 32,000 soldiers on the border between North and South Korea. Let’s see what happens.” The claims about the trade deficit are nothing new, despite significant evidence to the contrary, nor is the president playing security and economic issues off one another. However, if the president thinks he can leverage U.S. troops in Korea for any political or economic gain he is woefully mistaken.

The U.S.-South Korea military alliance is the backbone of the bilateral relationship. “Forged in blood” by the Korean War, the alliance continues to serve the shared interest of both countries through stabilizing the region as well as promoting economic openness and, since the late 1980s, liberal democracy. While the spread of communism is no longer the threat it was perceived to be during the Cold War, the North Korean threat remains, which is why even though South Korea is one of the world’s most advanced countries, the military component of these ties is vital. One of Trump’s biggest criticisms of the bilateral relationship is that South Korea has gotten away with exploiting the U.S. economy because of security concerns, yet the necessity of the alliance arguably helped to create a fairer trade deal for the United States. The alliance has also been the gateway to cooperation in a number of other global issues such as in space exploration, global health, and cybersecurity.

The closest the U.S. has ever been to withdrawing troops from the peninsula is also not coincidently the lowest point in U.S.-Korea relations. From 1977 to 1979, President Jimmy Carter was seriously considering the gradual removal of all U.S. troops from the peninsula over the South Korean government’s human rights record. The issue was a source of great consternation between the two governments and stoked Korean fears of abandonment. In the end, only about 3,000 troops left South Korea because the North Korean military proved to be a larger threat than previously thought. The potential for further withdrawal was resolved on its own after Carter pushed the decision back to 1981 in what would have been his second term in office, but by then there was new leadership in both Seoul and Washington.

Flash forward to today, the North Korean threat is similar in many ways but the evolution of Pyongyang’s nuclear and missile programs greatly raise the stakes for Washington. As a treaty ally, the United States is bound to defend South Korea in case of an attack. Thus, everything the alliance encompasses—including the 28,500 U.S. troops in South Korea, joint military exercises, and the U.S. nuclear umbrella—acts as a deterrence against North Korean aggression. Should this disappear now, tied to a negotiating tactic on trade or otherwise, South Korea would be at tremendous risk. This would jeopardize all of the added benefits the U.S. receives from relations with South Korea, including economic gains from bilateral trade as well as from regional stability. This is the same as it would have been in the late 1970s, though the benefits now are much are larger than they were 40 years ago. The biggest difference now, however, is North Korea is almost, if it isn’t already, capable of reaching the United States with a nuclear weapon. While the threat of military retaliation after an attack on the U.S. is undoubtedly a deterrent, this could easily be weakened if the U.S. were to abandon South Korea. After all, deterrence is a combination of both will and capability. Should the first half be questioned, Pyongyang could be emboldened to strike first.

Even if the president was trying to talk tough and has no intention to formally bring the issue up with Seoul, let alone follow through on it, the public discussion of troop withdrawal could have disastrous implications for U.S. interests. There is a confluence of factors, such as the return of great power politics between Washington and Beijing, now influencing Seoul that could force it to go off the well-worn path of firm resolve and close coordination with the United States. Though this is still the best way forward as CFR’s Scott Snyder argues in his new book “South Korea at the Crossroads,” should its feasibility come into question, Seoul may look to pursue other options even before the U.S. takes any action. Many of these options—such as obtaining nuclear weapons, which has gained some popularity in recent months, and closer ties with Beijing—would not only run counter to U.S. interests in the region, but on the global stage as well.

The best course of action for President Trump would be to immediately walk back the comments he made at the fundraiser and reaffirm the strength of the alliance by using well-trodden language, such as calling it “ironclad” and claiming there is “no daylight” between the two countries. At the very least it would be wise to quietly let this idea die. Trump may think it is a power play at the negotiating table, but should he pursue this further, he would actually be raising the white flag to Pyongyang and Beijing. He would risk setting off a chain of events that would ultimately put the U.S. in a worse position on trade with South Korea and at a strategic disadvantage in dealing with the most pressing regional security threat and global rival.

Kyle Ferrier is the Director of Academic Affairs and Research at the Korea Economic Institute of America. The views expressed here are the author’s alone.

Photo from Expert Infantry’s photostream on flickr Creative Commons.