The Pentagon's announcement identifying the US Marine Corps units that would relocate from Okinawa to Guam was the next step in a multi-year plan to redistribute US forces in the Asia-Pacific. Most US troops in the Asia-Pacific are currently based in Japan and South Korea, and is a holdover from World War II and the Korean War. But it's been half a century since those arrangements were put in place, and US defense policymakers have been keen to look at different configurations geared toward present and future, not historical, threats.
The presence of US forces on Okinawa has always been a sensitive political issue for Japan. Located 1,000 miles south of Tokyo, Okinawa is a Japanese prefecture and hosts roughly 26,000 of the total 47,000 US troops stationed in the country. Tensions between Tokyo and Okinawa have been a major factor in US force redistribution.
"The genesis of this plan [to move Marines to Guam] came from Japanese domestic politics," said Mira Rapp-Hooper, a senior fellow at the Center for a New American Security.
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President Barack Obama's "pivot to Asia" has called for a US military presence in the Asia-Pacific that is "geographically distributed, operationally resilient, and politically sustainable." The move from Okinawa to Guam meets all three requirements.
However, adjusting for an "evolving security environment in the Asia-Pacific" is also a nice way of saying the US is taking China's growing capability and confidence into account. China's growing capabilities include anti-access/area denial (A2/AD) operations, which are specifically geared at combating attempts to project power (i.e. US power) into the region.
While A2/AD (and the US response) is a giant can of worms (and beyond the scope of this article), the implication is that the US has to start thinking anew about how it positions itself in the region and how it wants to operate in future. So, US military planners are looking south from Korea and Japan toward the East China Sea, South China Sea, and Taiwan, and thinking about what threats are most likely.
When looking at possible scenarios in the region (i.e. anything from humanitarian assistance to major wars aka "contingencies," in Department of Defense parlance), a key element of military planning is response time and the ability to quickly "flow forces" to a given location. And this is what makes the location of current and potential US bases a tricky balancing act.
Okinawa sits just north of Taiwan (a.k.a. the Republic of China). Taiwan has been a sore spot for China for decades (the mainland seeks eventual reunification with Taiwan), and the US is obligated to help Taiwan maintain its defense capability under the provisions of the 1979 Taiwan Relations Act. That said, the US does not support Taiwan's independence, but in the event of a Chinese invasion of Taiwan, the US would face considerable pressure to intervene. Although the specific details of any potential US defense of Taiwan are classified, the US base at Okinawa is about 400 miles from Taipei, by far the closest major US military installation. Incidentally, Okinawa is even closer to the Senkaku Islands, contested by, among others, Japan, and China.
There are additional operational implications. Taiwan sits right in the middle of what is sometimes called "the first island chain," which is a set of major islands and archipelagos off the Asian coast, and is widely seen as the first natural line of defense in the event of a broader regional conflict between the US, its allies, and China.
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Should Taiwan be overtaken by mainland China, it would split the first island chain in half, cutting off US allies Japan and Korea (in the North) from other theoretical combatants located to the South, like Australia and the Philippines, and give China unimpeded access to the Pacific as a whole. US forces operating from Okinawa are a key component in planning for these types of contingencies.
Yet basing forces in Okinawa (particularly to reinforce Taiwan) comes with a whole slew of political complications with Japan, while Guam is US territory, and force deployments from Guam come without any strings attached. But if the US is moving forces away from Okinawa to Guam, is it sacrificing its ability to respond to an emergency situation in the region? Is the US weakening its position?
Not necessarily, said Navy Commander David Slayton, who is a national security research fellow at the Hoover Institution.
"It's dangerous to view this move to Guam in strictly a force-on-force schema, particularly just ground forces," he said. "One needs to remember, Marines are also stationed afloat [on ships]."
Slayton also pointed out that putting distance between US forces and China could be good thing. If fighting were to break out between Taiwan and mainland China, not only would a US commander at Okinawa have a crisis on his doorstep, but the close proximity of Okinawa to China may make the base a high-value target and put it in range of Chinese missiles.
Rapp-Hooper concurred, saying, "One of the US's great advantages is its ability to operate over long distances." This contrasts with China, whose expeditionary capabilities and force projection abilities are growing, but remain far behind those of the US. "The farther from China's shores you get, the less [China] is able to operate," she said.
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But given the forces being relocated are all Marines, what is the true significance of the move? Optics certainly play a role. Any time US forces start moving east, away from Asia (and particularly if they cross the international date line back to Pacific Command Headquarters in Hawaii), you start to hear rumblings about a US "departure" or "retreat" from the region.
"China is using this theme in their strategic communications; you can see this played out in China Daily often and other outlets that are communication mechanisms for the [Chinese Communist] Party, the [Peoples Liberation Army], and other party entities," Slayton said. "Likewise, in the US, opponents of the Obama administration point to this as another area where the US is creating a vacuum to be filled by others and ceding vital US interests in the region."
But other movements of US forces in the region may alleviate these concerns. The increasing enthusiasm for a US military presence around the region is striking and is a direct result of fears that China's ambitions in Asia will continue to grow. US Marines and Air Force assets are already based in Australia or will be soon. US littoral combat ships are on rotation in Singapore. An agreement is in place with the Philippines to welcome US forces back, on a rotational basis, to defense outposts that were part of US military planning for most of the 20th century.
There are discussions (and hopes) that Vietnam may be willing to have serious conversations about a US presence at Cam Rahn Bay (though Russia greatly complicates that conversation). But Vietnam is the last country to have fought a major conflict against China, back in 1979. So, basing US forces in Vietnam would be seen as an aggressive move, since it would put US forces on the far west side of the South China Sea, in a country bordering China, and just a couple hundred miles from installations in southern China and Hainan Island.
Farther away, the US military is also building its presence in Australia, building up to 2,500 Marines — a Marine Air Ground Task Force (MAGTF) — in the northern town of Darwin. While a MAGTF can't fight a major conflict all by its lonesome, it is a rather substantial combat force by local standards, and quite enough to provide for a host of non-combat missions.
The US military contingent rotating through Darwin is closer to the capitals of five Southeast Asian nations than it is to the Australian capital at Canberra. Australia also has a unique advantage as a host to US forces because it has plenty of room for 360-degree training exercises. So look for the MAGTF in Australia to engage nearby nations, including Indonesia, Malaysia, and others with bilateral, trilateral, and multilateral exercises.
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These new (and in some cases theoretical) plans run counter to narratives about US departure from the region.
"I think the growing commitments to [other] countries [in the region] offset the optics of forces moving from Japan to Guam," the RAND Corporation's Timothy Heath said. "There is little evidence that the United States seeks to withdraw from Asia. It is merely thinking about how best to position its forces smartly to improve operational resilience and strengthen its relationships with countries in Asia."
Nonetheless, "Some would argue that the US efforts have been weak and half-hearted towards the other [Asia-Pacific] countries, and I would agree," Slayton said. "We could be doing even more, and more committed confidence-building measures towards and with the Philippines, the South Koreans, Indonesia, Singapore, and Vietnam. We presently have more diplomats stationed in France than we do throughout all of Oceania."
The Okinawa/Guam moves don't exist in a vacuum, but represent the movement of one game piece from one part of the board to another, and are part of a larger rebalancing of US presence. The plan is that these and future moves will make US forces more flexible and responsive to the challenges of the day, rather than those of World War II, the Korean War, and the Cold War. But regardless of the specifics of the deployments, it will be a challenge for the US to balance military need, political sensitivities, and international optics in such a way that the US can be both prepared and be seen to be prepared in the region.
Follow Shannon Hayden on Twitter: @ShannonKHayden