Why does the United States still have military bases in Japan and South Korea?

As far as I'm aware, the bases are large, active, and the source of a reasonable amount of controversy within the host countries, whether it's sexual assault or traffic accidents.

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    From the host country perspective, military bases provide a large body of young people with disposable income who spend money in neighboring towns. They buy consumer items, rent apartments, eat and drink in restaurants, use airports, trains, and taxis etc. They also provide jobs for local civilians. You could probably find some figures around somewhere if you are interested as well as articles on the effects on the local economy following a military base closing.
    – Beo
    Commented Mar 6, 2017 at 15:46
  • Maybe some of the "reasonable controversy" could be linked to, just for documentation purposes. Traffic accidents doesn't sound very serious. Also, there are US bases in so many countries. Commented Mar 29, 2022 at 15:34

2 Answers 2


Why does the US have military bases in friendly countries?

  • Logistics: The US has military bases all over the world. This, in addition to things like aircraft carriers and air patrols, allows the US to respond quickly to unexpected threats.

  • Show of friendship: Many allies of the US depend on its military, in whole or in part, for their defense. Keeping a contingent of personnel and resources in the allied country reinforces the commitment of the alliance.

  • To facilitate allied military operations: During many missions, a coalition of allied forces will participate. This may involve things like e.g. loading French soldiers and British tanks onto an American plane on a military base in Germany.

  • Show of power: Having lots of bases all over the world is a way of intimidating enemies. Many US bases are concentrated around countries that pose a potential threat to the US and/or its allies.

Why East Asia in particular?

  • Historical reasons: East Asia was hit hard in WWII. During the Cold War, it became one of the focal points of the conflict. Communist influence from China and Russia spread into SE Asia and the US attempted to halt and contain it (see the Vietnam War and the Korean War). The amount of military activity in this area during the 20th century necessitated the establishment of local bases.

  • North Korea: North Korea is considered a significant threat to the region, especially to South Korea and Japan which are two of America's closest allies in the area. Keeping troops nearby discourages the DPRK from launching direct attacks, and helps US allies feel safe.

  • China: The US and China have a complicated relationship. There is currently conflict between the two powers and their allies regarding claims to the South China Sea, a conflict which has been simmering for some years now. Both sides have been positioning their respective militaries back and forth trying to gain an advantage. While neither side wants a confrontation, the threat involved requires keeping troops available nearby.

  • When referencing the impact of WWII on the Southeast Pacific, consider mentioning that there was already an active war in the theater for 4 years to start of WWII in the pacific Theater. Commented Dec 29, 2016 at 14:16
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    Probably a mention of restrictions on Japan's military capacity as part of the WWII end of hostilities agreement might be relevant. Commented Mar 6, 2017 at 16:51
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    "China: The US and China have a complicated relationship." It's not just America and Japan. Japan and China have a difficult relationship. Taiwan and China have a difficult relationship. The Philippines and China have a difficult relationship. The answer shouldn't make it sound like it is only America that worries about China.
    – Readin
    Commented Oct 14, 2017 at 3:44
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    I'd consider working in the additional reason (especially in SK) of the military forces as a Trip-Wire for deterrence thefreedictionary.com/trip+wire
    – Gramatik
    Commented Oct 31, 2017 at 16:08
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    Also consider that the host country generally wants these bases, even though some groups within the country may not. If the host country wants the bases removed, as happened with the Phillipines, they are.
    – jamesqf
    Commented Oct 31, 2017 at 19:05

Strategic & security interests. The United States need to have its fleet and army personnel stationed in Japan and South Korea to maintain a power balance in the area.

The Pacific Ocean is fairly "empty". Going east from the Japan Archipelago, there are few places where the US could station military personnel until one gets to Hawaii, around 4000 miles or 6000 km to the east of Japan.

Let's imagine a case where American soldiers leave South Korea and North Korea invades. Had there been no military bases to the west of Hawaii, it would take a long time to send military personnel to support South Korea.

Moreover, Japan officially doesn't have a military, and its defense expenditures and equipment are very limited compared to other countries of such size. Neither does it have a military draft, not even in times of war. South Korea does have an army, but North Korea's army is just much bigger. There is no way that South Korea could possibly have an army comparable to North Korea's. In the event of American evacuation from East Asia, a North Korea invasion (or at least aggression) would certainly be the case.

There is little possibility of overt military aggression by China, but there is still a concern here. If the US does not maintain military personnel in East Asia, it could eventually lose its grip over South Korea and Japan due to China's proximity to them, large trade volume with them (a FTA was almost signed), and of course China's ability to use force deterrence. South Korea and Japan probably wouldn't choose communism (or even less possibly Chinese style "socialism"), but they might turn to China as their main partner! So, to keep its grip over South Korea and Japan, the US has no choice but to continue to provide security to the two countries - by stationing troops there.

Do Japanese and Koreans like the G.I.s in their countries? Probably not too much. There have been protests against American military presence in both Okinawa, Japan and South Korea. However, do they want American soldiers to leave? Neither, because there will be unfathomable consequences to this.

  • as a purely anecdotal comment on North Korea invading South Korea, when I visited SK recently the few people I talked to all believed they would decisively win any war that broke out, and several claimed the only reason they hadn't invaded NK was pressure from the US/western Europe not to. Commented Jul 24, 2023 at 23:50
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    @RyanJensen: in terms of the ensuing conventional warfare, I totally believe so as well. NK military equipment does not hold a candle against the far more sophisticated South. But (1) China and Russia will likely intervene and (2) the north is nuclearly equipped and might use it to attack major cities in range (most of Japan, and, interestingly, most of north China), as a means of last resort, so no one can be sure what will the real outcome be.
    – xuq01
    Commented Jul 25, 2023 at 8:58

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