The Korean War: America vs China | Ask The Professor

0:03 Hi, this is John Meersheimer, and as you know, I'm answering questions from channel members. And today I'm gonna answer a question having to do uh with the Korean peninsula. Uh the member who sent me this question self-identifies as space come true. And he said that he would greatly appreciate it if I could make a video sharing my analysis of the causes and course of the Korean War.

0:41 Now, let me start by talking about the course of the Korean War and then talking about my understanding of its causes. The Korean War broke out on 25 June 1950 when North Korea invaded South Korea. And there were hardly any American troops in South Korea at that point in time. And therefore, it was a fight between North Korea and South Korea.

1:12 And there was no question that the North Korean troops were much more formidable than the South Korean troops. And they pushed very quickly the South Korean troops back to the bottom of the Korean peninsula. And at that point in time, when it looked like the North Koreans were going to triumph and would end up unifying all of Korea, the United States came into the fight.

1:39 And the United States rather quickly pushed the North Koreans all the way back to the 38th parallel. There was the famous landing under the leadership of General Douglas MacArthur at Incheon. And in effect, we got into the rear area of the North Korean forces which were retreating and inflicted a devastating defeat on the North Koreans.

2:08 At that point in time, the big question was whether or not the United States should cross the 38th parallel. And you understand that the 38th parallel was the dividing line between North Korea and South Korea. And the United States, with General MacArthur in the lead, decided to cross the 38th parallel and in effect to roll up the North Koreans.

2:34 And should that happen, of course, Korea would be unified under the auspices of the North Koreans, excuse me, of the South Koreans. Had the North Koreans succeeded in their offensive in decisively defeating South Korea, all of Korea would have been unified under the auspices of the North Koreans. But here we are crossing the 38th parallel in the summer of 1938 and heading up towards the Yalu River.

3:05 And the Yalu River is the northernmost border of North Korea, and it separates China from North Korea. What happens is that the Chinese come into the fight. I think it was on October 19th of 1950. In other words, in the fall of 1950, as U.S. forces are moving towards the Yalu River. They, of course, have now crossed the 38th parallel.

3:34 They're heading towards the Yalu River. And the Chinese make it clear that this is not acceptable to them. And we don't listen. We continue to push forward. And what happens is that the Chinese come into the fight. And the war then shifts against the United States because the Chinese do very well against what are effectively overextended American forces in North Korea.

4:01 And the Chinese push the Americans down south of the 38th parallel. And eventually the Americans claw their way back to the 38th parallel. And a war takes place between October 1950, when the Chinese come in to North Korea, and July of 1953, when the war is finally settled. The war takes place between the United States and China.

4:35 Some people, when you talk about the Korean War, think that this was a war between the United States and North Korea. That was true at the very beginning of the war. But after October 1950, it was a war between the United States and China. And again, that lasted until 1953, July 1953, when you finally get an armistice.

4:59 You don't get a peace agreement, you get an armistice. The fighting stops. And you basically return to the status quo ante. You return to the 38th parallel, with the South Koreans on one side and the North Koreans on the other side. And of course, the United States remains in South Korea. The United States, up to this very day, keeps a large contingent of American troops in South Korea.

5:28 So that's the basic course of the war. But before I go to the causes of the war, I just want to make one more point about the course of the Korean War, and in a sense, put this into a broader context. It's very important to understand that the Korean War served to militarize the Cold War. Up until the Korean War started in June of 1950, there is no question that there was a Cold War between the United States on one side and the Soviet Union on the other side.

6:02 But the conflict between the two superpowers had not been militarized in any significant way. Yes, NATO had been created in 1949, which of course is before the Korean War, but the fact is that the militarization of the Cold War, which was present throughout almost all of the Cold War, doesn't really start until the Korean War.

6:29 And the Korean War galvanizes the United States to really take seriously, building up its military forces and viewing the Soviet Union as a serious military threat. So the Korean War is very important, not only for what happens inside of Korea and in Northeast Asia, but it's also very important because of the effect that it has on the Cold War, that is, to militarize the Cold War.

6:55 But let me talk about the causes now. If you're going to talk about the causes of the Korean War, I think you have to talk about what caused North Korea to attack South Korea on 25 June 1950, what caused the United States to come into the fight shortly after the war started, and then what caused the Chinese to come into the fight in October of 1950.

7:19 With regard to North Korea, I think it was quite clear that what North Korea wanted to do was to unify Korea under the auspices of Pyongyang. If you go to Korea today, it becomes very clear very quickly that South Koreans are deeply committed or deeply interested in unifying the two Koreas. And that logic applied to North Korea in 1950.

7:46 And I believe that the North Koreans were confident, as they should have been, that they could win a quick and decisive victory against South Korea. And that's why they invaded. It's quite clear that they had the blessing of the Soviet Union. And here we're talking about Joseph Stalin, who was in charge of the Soviet Union at that point in time.

8:08 And given the formidable military capabilities the North Koreans had, vis-a-vis the South Koreans, they decided to invade. And they came close to winning, but then the United States came in. So my point here with regard to the North Koreans and why they invaded, that's straightforward. The aim was unification of the two Koreas.

8:28 Now, why did the United States come in? It's very interesting, but before the Korean War started, the Secretary of State Dean Acheson made a huge blunder. And he basically said that what happened in Korea was of no strategic consequence to the United States, implying that the United States would not come in to a war between North Korea and South Korea if the North was winning.

8:53 However, once the war started, it quickly became clear to Acheson and others that because Korea is located in Northeast Asia, very close to the Soviet Union, that Northeast Asia is an area of great strategic significance to the United States, and therefore the United States could not afford to allow an ally of the Soviet Union, indeed a close ally of the Soviet Union, North Korea, to unify all of Korea, especially because of the fact that Korea was so close to Japan, which was our principal ally in East Asia at the time.

10:11 We thought that North Korea winning in South Korea would be a strategic blow to the American national interest. And that accounts for why we came in. That brings us to the final part of the story, which is why did the Chinese come in in October of 1950? Well, the fact is that North Korea is adjacent to China.

10:37 And as I said before, after the United States crossed the 38th parallel, its troops were heading toward the Yalu River, which is the border between North Korea and China. From China's point of view, the idea that American forces would occupy North Korea, that Korea would be unified under South Korea's auspices, and therefore South Korea, or I should say, and therefore a united Korea, would be an ally of the United States, was just unacceptable to the Chinese.

11:15 In a very important way, this is akin to the situation involving bringing Ukraine into NATO. From a Russian point of view, having Ukraine, which is adjacent to Russia, which sits right on Russia's border as a member of the NATO alliance, was unacceptable to the Russians. And this, of course, as I've said many times, is what precipitated the Ukraine war.

11:43 The same basic logic applies here. The Chinese found it unacceptable that you would have a unified Korea under the auspices of South Korea that was an ally of the United States, that would therefore allow the United States to station troops right on China's border, right on the Yalu River. And to prevent that from happening, the Chinese came into the war in the fall of 1950, and they fought continuously until July 1953 to keep the Americans either at or below the 38th parallel, because that was a vital strategic interest for China.

12:27 So I think that in sum explains why the North Koreans attacked to begin with, the Americans then came in, and the Chinese after that came in. One final point here: my interlocutor asked me also what I thought of the situation or the relationship between North Korea and South Korea today, and what that meant for stability on the Korean peninsula moving forward.

13:00 Very quickly, North Korea today has nuclear weapons. There is no way that South Korea would attack North Korea, or that the United States would look to pick a fight with North Korea, because again, North Korea has nuclear weapons, and North Korea could use those nuclear weapons not just against South Korea, but against American forces in South Korea, and North Korea could use those nuclear weapons against Japan, which is located close by.

13:46 And the last thing the United States and South Korea and Japan want is to see North Korea use nuclear weapons against them. So North Korean nuclear weapons provide great stability on one side of the equation. Now one might say South Korea doesn't have nuclear weapons of its own. But the fact is that nuclear weapons don't provide any significant offensive capability for North Korea.

14:17 So it's not that North Korea, it's not like North Korea can use those nuclear weapons of its own to coerce South Korea or to attack South Korea or to do the same thing with Japan. It's just not in the cards. Nuclear weapons are a formidable deterrent for sure, but they have remarkably little offensive military capability.

14:40 Moreover, in this case, South Korea is effectively joined at the hip with the United States, because the United States has hard numbers of troops deployed in South Korea, and the United States, of course, has a nuclear deterrent of its own. So if the South Koreans were to use their nuclear weapons for offensive purposes against U.S.

14:59 troops or against South Korea or against Japan, it's almost certain that the United States would retaliate in kind. And North Korea certainly doesn't want that. North Korea wants its nuclear weapons because that's the best guarantor that it will survive. But it, again, is not a situation where nuclear weapons provide North Korea with much of an offensive option.

15:24 So I think when you look at the overall picture here, even though only North Korea has nuclear weapons and South Korea does not, I think the situation on the Korean peninsula is quite stable. I find it difficult to imagine that a war will break out between North Korea and South Korea in the foreseeable future.

15:47 This is not to say that it couldn't happen, but I think the chances of it happen are remarkably slim. And a lot of that has to do with the fact that North Korea has nuclear weapons and that South Korea is joined at the hip with the United States. That concludes my comments on this excellent question.

16:09 Thank you very much for listening.