By Grant Newsham, Senior Research Fellow, Japan Forum for Strategic Studies
US military bases on Okinawa remain a contentious issue, and probably always will be. Opposition to the military bases is owing to a combination of things; to include local politics, historic resentments of mainland Japan, anti-military feeling, and even a need by base opponents to pressure the central government to continue handsome subsidies to Okinawa. Millions of words (probably more) are written each year about the Okinawa base issue. I will add some more, but this commentary will focus on the role of US military bases on Okinawa as a ‘deterrent.’
One should first ask what is being ‘deterred’? Put simply, US forces forward deployed on Okinawa as elsewhere in Japan are intended to deter countries that would attack other nations or seek to seize land territory or dominate seas and airspace that are either international global ‘commons’ or owned by somebody else.
For many years, the Okinawa bases were seen as playing a role in deterring a North Korean attack on South Korea. However, in recent years the People’s Republic of China (PRC) has strengthened the case for the US bases’ deterrent value. The PRC’s rapid military build-up, increasing Chinese military activities throughout the region, and claims to nearly all of the South China Sea have unsettled China’s neighbors — nearly all of whom look (even if furtively) to the United States to restrain China.
Why do Okinawa bases deter?
The Okinawa bases alone do not deter China or anyone else. But they are an important part of a larger network of American resources, power, and influence that give the PRC pause. One first notes Okinawa’s location. It is near Taiwan, close to contested areas in the East China Sea and the South China Seas, and not far from the Korean Peninsula. Okinawa is a perfect place from which to deploy and conduct a range of military operations to counter an aggressor or someone seeking to upset long established rules regarding freedom of navigation and flight, and even international boundaries.
Time and distance still matter in warfare. Being close to where one will operate allows a more rapid and comprehensive response. Okinawa-based forces are able to move just about anywhere in Asia in a matter of days or even hours. This response time is much shorter than if based elsewhere in Japan — and weeks or months faster than US-based forces, even if based in Hawaii. Also, being nearby allows you to stay ‘on-scene’ longer. Try patrolling the South China Sea from bases in Hokkaido or Hawaii. By the time forces arrive it is almost time to go home.
An illustration that helps one understand the importance of time and distance (and location) is to consider the effect of moving Tokyo Metropolitan Police Headquarters to Gotemba — 60 miles west of Tokyo. Theoretically, TMPD might send patrols into Tokyo for a few hours a day or as needed to respond to emergencies — before driving back to Gotemba to refuel. This is obviously less effective for maintaining law and order than actually being based in Tokyo. Similarly, US bases on Okinawa are located near where trouble might occur — and therefore better able to respond and to deter adversaries.
China understands the importance of location
Chinese behavior in the South China Sea shows it understands the role of ‘location’ as a part of deterrence. PLA forces operating out of Hainan Island can operate throughout the South China Sea. However, China’s recent island-building efforts much further south in the South China Sea demonstrate a clear understanding of the importance of basing forces ‘forward’ in the area one wants to control or influence.
This forward location facilitates military operations — allowing a more rapid and constant presence — and it also ‘deters.’ Some critics have pointed out that China’s new man-made islands are indefensible in the event of war with a competent enemy. This is true enough, but it misses a larger point. Once the island bases – even with small military detachments in place — are established, they effectively ‘deter’ other countries from striking back — or even applying pressure — out of fear of provoking or starting a war with China. Thus, these small islands with military forces placed on them can restrain a potential adversary’s behavior. This restraining effect is otherwise known as ‘deterrence.’
US bases on Okinawa from which US Air Force, US Navy, US Marine, and US Army forces operate serve a similar function in bolstering American defense power and the possibility of using it in the region — as Beijing would probably admit.
Aren’t US forces assigned to US bases on Okinawa too small to deter?
Some commentators argue that there are not enough US forces on Okinawa to deter an aggressor, much less make a difference in the event of a major conflict in Asia. Besides the fact that even a small number of troops, ships, or aircraft rapidly deployed can make a difference, this argument overlooks the fact that in the event of a more serious contingency, Okinawa-based forces will be reinforced. They are intended to be employed as part of a larger effort involving US forces from overseas. Only a rash opponent would care to take on the full might of the United States.
A similar dynamic applies on the Korean Peninsula. The relatively small number of US Army troops in South Korea stationed near the DMZ have a limited warfighting capability, but force the North to run the risk of bringing the full weight of the United States in the event of an attack. This deterrent effect has worked for many decades.
Also, one should remember that deploying US troops from a distance (i.e. the US mainland or even Hawaii) is almost always a difficult domestic political decision. With forward deployed troops, the decision has mostly already been made — and if US troops are targeted or harmed, the certainty of a response is near 100 percent. This gives adversaries pause.
It is, of course, possible to reduce US forces (and bases) on Okinawa to a point where they are operationally irrelevant or ineffective — and therefore of little deterrent value from a purely military standpoint. Similarly, such a reduction in forces and bases might easily be viewed by an adversary such as the PRC as a weakened US commitment to defending Japan writ large.
The ‘political’ deterrent effect of US bases on Okinawa
Ultimately, US bases on Okinawa — with all the challenges and costs they involve — demonstrate a political commitment on the part of both governments — to include America’s promise to defend Japan. This sort of commitment is closely watched as an adversary decides how much to push. One recalls the classic example of Saddam Hussein miscalculating the United States’ willingness to defend Kuwait in 1990 that led to the First Gulf War.
One often detects a degree of puzzlement on the PRC’s part over the US’s willingness to defend Japan –and particularly certain territory in the Ryukyus, such as the Senkaku Islands. Solidly linked US and Japanese forces that are able to operate effectively together – to include forces based on Okinawa — are ultimately evidence of a strong political link between the two countries. This directly affects deterrence.
The deterrent effect of American bases on Okinawa depends heavily on the state of the US-Japan political relationship. The stronger the political relationship, the more likely the US will use the bases (and its other military and non-military resources) to defend Japan – and the more likely it is that the Japanese government will make the necessary efforts to preserve the US bases. One tends to depend on the other.
In this regard, the US and Japan should seriously consider integrating JSDF forces as fully as possible onto US bases in Okinawa — to include bringing the bases under Japanese control, such as at Atsugi and Misawa air bases. This would be politically beneficial as well as operationally useful. The deterrent effect of US and Japanese forces operating as ‘full’ allies and completely interoperable would be immense. This combination of military and political linkage has a deterrent value of its own and gives PRC strategic and operational planners considerable headaches.
Although not widely reported in the press, PRC political warfare efforts on Okinawa to create opposition to US bases and other friction for the central government demonstrate China’s awareness of political deterrence arising from a strong US-Japan relationship. Such political warfare efforts are ongoing in Guam and the Commonwealth of Northern Marianas (CNMI) as well — where additional US bases are being built or planned. Importantly, the Guam/CNMI bases are intended to augment US bases on Okinawa and provide strategic depth and enhanced deterrence for US military capabilities in East Asia.
Political deterrence also extends to third countries. The presence of US forces in Japan — and on Okinawa — is, as noted earlier, something many other regional nations desire and find reassuring. This tends to bolster their willingness — both individual and collective — to stand up to Chinese threats and/or blandishments — thus, deterring Chinese behavior that would otherwise be even more aggressive and assertive.
Can’t US bases on Okinawa be moved to mainland Japan?
Of course they can, and the PRC would think this is a splendid idea. However, the aforementioned ‘time and distance’ problems — and consequently weakened deterrence — would apply. Moreover, such a move would suggest a weakened US-Japan political relationship (and lessened deterrence) by virtue of Japan’s central government being unwilling to make the political effort needed to maintain US bases on Okinawa. Additionally, moving US bases to mainland Japan would leave a vacuum. Vacuums get filled, and it is possible the PRC will fill this vacuum. But it is almost unthinkable that a future Japanese administration would allow this to happen as the result of a drastically reduced military presence on Okinawa’s main island in light of the PRC threat. Thus, even if US forces leave their Okinawa bases, JSDF forces will certainly replace them.
Importantly, in the absence of a US military presence on Okinawa, Chinese forces would be facing off more or less directly with Japan Self Defense Force units. Removing the deterrent effect on the PRC of the fear of harming US troops would be dangerous given deep-seated Chinese resentment of Japan and an increasing belief the PLA is a match for the JSDF. In the absence of ‘deterrent’ US forces on Okinawa, expect the PRC to push and ratchet up the pressure on Japan — and in the Ryukyus and the East China Sea, to which China has stated it is rightly entitled. This is dangerous.
Other ideas that have been considered for reducing US bases and force presence on Okinawa while maintaining adequate operational and deterrent capability include a ‘virtual presence’ scheme and a scheme for ‘pre-positioning’ US equipment and flying in troops when contingencies arise. These are both doubtful concepts in terms of the ability to conduct effective military operations — and as importantly — to deter unacceptable behavior by regional nations.
The ‘virtual presence’ solution calls for rotating forces, particularly US Marines, though it applies just as well to Air Force and US Navy units through the region for training, without actually having any bases in the area. However, without a single location serving as a ‘center of gravity’ from which military — and Marine — power is seen to derive, there would always be something ephemeral about its presence, and suggests the US is not really serious about its promise to defend Japan and its own interests.
The ‘prepositioning’ school of thought claims US forces and Marines only need to have supplies and equipment staged on Okinawa, with troops flying out in the event of crisis. However, it is a truism that it is better to be located and to train in the region where you operate — just like a baseball team does best when practicing and playing at its home field. Also, pre-staged supplies and forward-based troops are viewed differently by adversaries. One is a vague promise of intervention, the other is a near certainty.
Calculating the deterrent effect of bases and/or forces is always an imprecise business. Perhaps the most important determinant is the degree of commitment and willingness of one country to sacrifice for another. To date, the US-Japan defense relationship and the maintaining of US bases on Okinawa for over 40 years after Okinawa’s reversion to Japan has maintained peace and stability in Northeast Asia. This has also had a calming effect in other parts of the region.
The Government of Japan obviously values the US bases on Okinawa or it otherwise would have closed them down — as is quite doable under the US-Japan Defense Treaty. However, the Japanese government must explain clearly and forcefully to the Japanese public why these bases are necessary for Japan’s national defense if it hopes to keep them. To date, no Japanese administration has done what is necessary in this regard. Maybe someday one will — as the more secure the US Okinawa presence, the greater the deterrent value.
Importantly, deterrence has never been tested quite like it is today. The US military presence on Okinawa is, as noted, operationally important and also a measure of the US-Japan political relationship. Our adversaries know this, although in both the US and Japan many observers and commentators downplay the deterrent effect of US bases on Okinawa.
Perhaps the ultimate test of the US Okinawa bases’ deterrent value is to remove the US military presence or drastically reduce it. Do so, and we will soon discover that they were a deterrent — and a good one indeed.
Originally published in Japan Forum for Strategic Studies Quarterly Report – October 2015
 The US military forces based on Okinawa are principally composed of the following: US Air Forces at Kadena Air Base, US Marine forces located at several camps on the island and the well-known Futenma Marine Corps Air Station, US Naval forces located at White Beach – although the Navy ships are home-ported elsewhere in Japan, and a small US Army detachment at Torii Station. The available Air Force, Marine, and Naval forces provide US commanders with a substantial and immediately usable combined arms force that can handle a range of contingencies throughout the Indo-Asia-Pacific region. The Okinawa bases and resident forces play fundamental roles in US military regional contingency plans.
Grant Newsham is a senior research fellow at the Japan Forum for Strategic Studies in Tokyo. He is a retired US Marine Officer and a former US Diplomat and business executive with 20 years of experience in Japan.