Pentagon Prepares for Island Combat in the Pacific as US-China Tensions Rise

As U.S. tank and infantry forces were fighting their way from Normandy to the Rhine in the pivotal land battles of World War II, other U.S. forces were conducting equally ferocious battles to expel Japanese forces from the Philippines and other islands of the Western Pacific — a long and bloody campaign that culminated in the struggle to capture Iwo Jima. Since then, the prospect of major ground warfare in Europe has never disappeared — look at Ukraine today — but the notion of another major amphibious campaign in the Pacific has largely evaporated. Recently, however, the U.S. Army and Marine Corps have begun preparing for precisely such a contest as China has emerged as the principal adversary to U.S. hegemony and neighboring Pacific islands have acquired fresh strategic significance.

Any major U.S. conflict with China, it is widely believed, will largely entail air and naval operations in China’s maritime areas, notably the East and South China Seas and the waters surrounding Taiwan. Such a clash, strategists assume, will involve intense air and sea battles for control of these areas. But, as in World War II, the fighting will also envelop any islands housing the air and naval bases of either side, such as China’s installations on islands in the South China Sea and U.S. bases in Japan, Okinawa and the Philippines. Aside from air and missile attacks on these island facilities, either or both sides may seek to occupy them through amphibious assault, resulting in the sort of brutal combat seen in those same areas during World War II.

These islands are all part of (or enclosed within) what Chinese strategists call the “the first island chain” — the long string of archipelagos stretching from Japan in the north to the Ryukyus and Taiwan in the middle and the Philippines and Borneo in the south, together acting as a sort of barrier to Chinese naval projection into the greater Pacific. (Strategists also speak of a second, outer island chain, consisting of the Mariana Islands and the western Caroline Islands.) The United States has long maintained a major military presence on islands up and down the first chain, both to project U.S. power into the region and to sustain U.S. combat operations in the event of a war. These include the major concentration of Air Force and Navy forces in Japan, the large Marine Corps contingent on Okinawa and bare-bones facilities in the Philippines. Along with any U.S. ships in the area, these bases would be among the primary targets for Chinese air and missile attacks at the onset of a U.S.-China conflict, followed, conceivably, by amphibious assaults aimed at occupying or demolishing them — which would no doubt provoke an aggressive U.S. response.

Located between the Chinese coastline and the first island chain are several contested island groups — the Spratly Islands in the South China Sea and the Senkaku Islands in the East China Sea — that could also become sites of U.S.-Chinese fighting in the event of a future conflict. The Spratlys are claimed in their entirety by China and in part by Brunei, Malaysia, the Philippines and Vietnam; the Senkakus (called the Diaoyu by the Chinese) are claimed by both China and Japan.

Both island groups have witnessed clashes between Chinese vessels and those of the other claimants in recent years, and the U.S. has vowed to assist its allies in defending their territorial claims against future Chinese harassment. Should China attempt to test this pledge in some significant fashion — say, by seizing islands now occupied by Filipino personnel — U.S. forces might engage in an amphibious operation to repel such an attack. A Chinese attempt to occupy the Senkakus — now administered by Japan — could produce a similar result, especially given President Biden’s recent assertion that the U.S. mutual defense treaty with Japan extends to the Senkakus.

To further complicate the picture, China has established military installations on some of the islands and atolls it claims in the South China Sea, in some cases using sand dredged from the seafloor to expand their size to allow the construction of airstrips. These installations, outfitted with an array of anti-air and anti-ship missiles, pose a potential threat to U.S. and allied warships operating in the area and so would constitute a prime target for amphibious assault in the event of a major U.S.-China conflict.

Restructuring the Force

With China now identified by the U.S. Department of Defense as the most dangerous, or “pacing” threat to U.S. national security, all of the military services have been instructed to prepare for a U.S.-China conflict. Accordingly, both the U.S. Army and the Marine Corps are restructuring their Asia-oriented forces — those committed to the Pentagon’s Indo-Pacific Command (INDOPACOM) — to be capable of conducting multiple offensive and defensive operations throughout the Western Pacific. This has generally entailed lightening their arms and equipment to allow for easy deployment and acquiring more forward operating bases in the region. Both also seek new mobile missile systems (often called “precision fires”) for attacks on enemy ships and land installations.

The Marine Corps, for example, is shedding its post-Cold War emphasis on conventional land operations and reverting to its earlier incarnation as a lightly armed amphibious force, optimized for island-hopping operations in the Pacific.

“We need to do less duplication of a second sort of land army and more to provide the nation unique capabilities that an amphibious and maritime and expeditionary crisis response force provides,” Marine Corps Commandant General David Berger said in 2020.

Berger’s vision for the Marine Corps is spelled out in a strategic blueprint he commissioned in 2020: “With the shift in our primary focus to great-power competition and a renewed focus on the Indo-Pacific region,” the plan indicates, the Marines have “a requirement for smaller, lower signature and more affordable amphibious ships and … affordable, distributable [combat] platforms.” To finance the procurement of all these new platforms, Berger proposes eliminating all of the Corps’ tanks and most of its heavy artillery companies.

The U.S. Army, while retaining its traditional focus on ground combat in Europe and the Korean Peninsula, has also increased its planning for island battles in the Pacific. Under a 2021 plan commissioned by Army Chief of Staff Gen. James C. McConville, called “Army Multi-Domain Transformation,” the service will restructure its Pacific-oriented forces to permit a rapid response to future Chinese expansion in the Indo-Pacific, whether by “inside” forces located on islands in the region or “outside” forces that can be rushed there by enhanced logistical capabilities.

“Advanced adversary capabilities and capacity will necessitate large amounts of low-signature, distributed, lethal ‘inside forces’ that maneuver rapidly, aggregating and dispersing as required,” the Army paper indicates. Echoing Berger’s vision for the Marine Corps, it suggests that in future Pacific battles, “constant displacement will be the norm: units will tend to have broad fronts, will rarely have secure flanks, will engage in compartmented battles, and will not have air and naval superiority.”

Training for Pacific Island Wars

To put all these plans into practice, both military branches have been conducting large-scale combat exercises in the Western Pacific and securing new basing facilities there.

Especially indicative of the Marines’ new thinking is a series of exercises called “Resolute Dragon,” held in conjunction with the Japan Self-Defense Forces (JSDF) over the past two years. Although ostensibly focused on defending Japan’s main islands, the exercises appear to embody a larger strategic sweep, involving joint amphibious operations throughout the region.

During Resolute Dragon 2021, held December 4-17 of that year, some 2,650 Marines and 1,400 soldiers from the JSDF engaged in simulated maritime assault operations. A principal aim of the 2021 exercise was to test the Marines’ concept of Expeditionary Advanced Basing Operations (EABOs), or the installation of minimalist facilities on contested island territories. During the exercise, the joint force established 12 such facilities up and down the length of Japan, demonstrating the concept’s validity. This experience will be used to inform Marine planning throughout the Indo-Pacific region, noted Col. Matthew Tracy, commanding officer of the 4th Marine Regiment, one of the participating units. “They’ll try and do what we’re doing at the tactical level, Pacific wide,” he told Breaking Defense.

Resolute Dragon 2022, held last October, retained many features of the 2021 version but included an additional twist: while 1,600 U.S. Marines were training alongside JSDF soldiers in Japan, another 1,900 were partnered with Philippines Marine Corps personnel in a parallel exercise, KAMANDAG 6, which included amphibious assault operations along the eastern and northern coasts of Luzon. Significantly, KAMANDAG 6 (an acronym for “Kaagapay Ng Mga Mandirigma Ng Dagat,” Tagalog for “Cooperation of the Warriors of the Sea”) also involved participation by the JSDF Amphibious Rapid Deployment Brigade and Republic of Korea Marines, suggesting the multinational and region-spanning nature of U.S. planning for future amphibious operations.

Like the Marine Corps, the U.S. Army has also begun to train its forces for rapid deployment to potential island combat sites throughout the INDOPACOM region. Many of its exercises have been conducted on the island of Guam, an unincorporated territory of the United States located at the southern tip of the Mariana Islands, about 5,800 miles from San Francisco but only 1,900 miles from Shanghai. Guam houses Andersen Air Force Base, one of the most important U.S. bomber bases and logistical facilities in the Western Pacific.

In June 2020, for example, some 400 paratroopers from the 4th Infantry Brigade Combat Team of the 25th Infantry Division, based at Joint Base Elmendorf-Richardson, Alaska, parachuted into Guam as part of an Emergency Deployment Readiness Exercise. In what appears to be a mock assault on a Chinese-occupied island like those artificially expanded atolls in the South China Sea, the paratroopers first secured Andersen Air Force Base and then seized other objectives in the area. “This scenario tested our ability to execute real-world missions and demonstrated that we are capable of deploying anywhere in the U.S. Indo-Pacific Command area at a moment’s notice,” said Col. Christopher Landers, commander of the airborne combat team.

Guam was again the site of a simulated airborne assault one year later, as part of the Army’s Exercise Forager 2021. On this occasion, soldiers from the 82^nd Airborne Division and the 1^st Special Forces Group, based at Fort Bragg, North Carolina, were joined by Japanese paratroopers in the mock invasion. In a test of the Army’s ability to project power into the region directly from the United States, the participating U.S. paratroopers were flown 8,000 miles from Joint Base Charleston, South Carolina, to the Guam drop location. That JSDF soldiers also participated in the exercise again demonstrates the Pentagon’s commitment to joint operations throughout the western Pacific. Said one Special Forces officer participating in Forager ’21, the mock assault “showcases the ability to project bi-lateral force throughout the first, second island chain and the whole INDOPACOM region.”

Acquiring Forward Operating Bases

In addition to these training and restructuring efforts, the Army and Marine Corps are preparing for possible island battles in the Western Pacific by acquiring additional bases in the area, typically bare-bones facilities that do not house a permanent U.S. military garrison but are equipped to support expeditionary operations, or assaults on distant enemy locations.

The first such installation to be established is the Marine Rotational Force (MRF) in Darwin, Australia. Located by the Timor Sea in Australia’s Northern Territory, the MRF facility is closer to the southern Philippines and the South China Sea than to, say, Sydney or Melbourne. As a result of an agreement signed by President Obama during a visit to Australia in 2011, the U.S. presence has grown from just 200 Marines in the first rotation to approximately 2,500 today. While in Australia, these troops engage in a six-month stint of training and exercises, usually in conjunction with Australian military personnel. In the event of a war with China, the Darwin facility could also be used to support combat operations throughout the South China Sea area.

Just recently, on February 2, Secretary of Defense Lloyd Austin signed an agreement with Philippine President Ferdinand Marcos Jr. affording the U.S. military access to four more bases in his country, in addition to four other facilities the Pentagon has been allowed to use under a previous accord. The new facilities, like the four covered under a 2014 agreement, do not involve a permanent U.S. military presence but allow for the use of runways and logistical facilities. Should the Philippines come under attack by China, they could be used to house and support any U.S. forces committed to the former’s defense under the U.S.-Philippines mutual security pact.

The acquisition of these bases, along with all the other developments described above, demonstrate just how far the Army and Marine Corps have proceeded in their efforts to prepare for major combat operations in the Western Pacific. Clearly, senior Pentagon officials believe that a war with China is becoming increasingly likely, and that, when and if such a conflagration erupts, it will entail heavy fighting over key islands in that region.

Senior leaders of both countries claim that war is not inevitable and that they are determined to erect “guardrails” against the escalation of minor incidents, such as an unintended air or ship collision in the South China Sea. Indeed, both President Biden and Xi Jinping of China agreed to accelerate such efforts at their meeting in Bali on November 14. Since then, however, both sides have engaged in provocative actions — such as the Chinese spy balloon intrusion and increased U.S. military aid to Taiwan — that have forestalled progress in this area.

With diplomacy making little progress in resolving U.S.-China tensions, both sides are continuing to arm and train their forces for combat over the critical island bases of the Western Pacific. And while these contests may not resemble those of World War II in every respect, the simulated battles enacted in exercises like Forager and Resolute Dragon suggest they will be equally ferocious and bloody.