Today, China enjoys a positional advantage within the First Island Chain, which allows the People’s Liberation Army (PLA) to enjoy interior lines of communication and supply to move forces more efficiently along an inner arc, compared to American-led coalition forces that will operate on an outer arc. This strategic advantage facilitates faster mobilization and concentration of military power by the PLA, enhancing its ability to project force within the region.

To counter China’s geographic advantage, Andrew F. Krepinevich Jr. argues in Archipelagic Defense 2.0 that the United States and its coalition partners should prioritize establishing robust fixed defenses at critical points along the First Island Chain (an arc of islands stretching from Japan to the Philippines). These fixed defenses can stock deep magazines, harden positions, and complicate PLA scouting efforts. By situating ground forces on key islands these defenses can slow down if not prevent China’s aggressive mobility and provocation capabilities.

The islands of the First Island Chain, along with the flanking states (South Korea in the north and Vietnam in the south), form natural chokepoints that can impede China’s access to open seas. Coalition forces can play a crucial role in enhancing defense by focusing on these chokepoints. Deploying undersea sensor networks, submarines, unmanned underwater vehicles (UUVs), antiship missiles, and mines can effectively limit PLA naval and air operations.

Ground forces can significantly contribute to the defense of maritime chokepoints as well. By establishing strongholds at key locations, they can free up more mobile forces for counter-concentration efforts. This static defense strategy, coupled with mobile strike capabilities, creates a layered defense system that complicates the PLA’s operational planning and execution.

On March 8, 2024, the Philippines Secretary of National Defense Gilberto C. Teodoro Jr. emphasized the importance of the Comprehensive Archipelagic Defense Concept (CADC). The CADC leverages the positional advantage of the Philippine section of the First Island Chain. This arc forms a natural barrier against Chinese maritime expansion, and its strategic significance lies in its potential to restrict the People’s Liberation Army Navy (PLAN) movements.

The Enhanced Defense Cooperation Agreement (EDCA) between the Philippines and the United States could do more to enhance archipelagic defense. The Balikatan Exercise in April 2024 exemplifies the ongoing military cooperation aimed at strengthening defense capabilities in the region.

However, recent developments, such as the planned construction of a new port in the Batanes Islands, without US help, highlight the Philippines’ efforts to bolster its infrastructure and defense independently. This move, while avoiding direct US involvement, ensures that the Philippines remains vigilant and prepared to counter potential threats from Chinese expansion. The strategic importance of the Batanes Islands is that it is located less than 200 kilometers from Taiwan and separated by the Bashi Channel. These islands, along with Itbayat and Basco in the Luzon Strait, form critical chokepoints in the western Pacific and the South China Sea. In the event of Chinese aggression towards Taiwan or the Philippines, controlling these islands becomes paramount.

For its part, China has built bases on three atolls (Subi Reef, Fiery Cross Reef, and Mischief Reef) and Taiping Island (Itu Aba Island) and is continually harming Filipino sailors and ships within the sovereign territory of the Philippines. Further, Chinese military activities near Japan are increasing such as when the PLAN sent survey ships, like the Chen Jingrun, into Japan’s uncontested waters between the Iriomote and Yonaguni Islands.

The addition of the tenth dash to the nine-dash line is China’s claim to Senkaku, which necessitates a comprehensive archipelagic defense strategy. The Philippines and Japan, in collaboration with the US and its allies, must enhance fixed defenses, leverage positional advantages, and fortify critical chokepoints within the First Island Chain. By doing so, they can effectively counterbalance China’s assertive maritime claims and increasing hostility.

The CADC, supported by initiatives like the EDCA represents the beginning of a much-needed effort towards safeguarding the Philippines’ national sovereignty and maintaining the balance of power in the Asia-Pacific region. As geopolitical dynamics continue to work against Taiwan’s de facto independence, the US must work closely with Japan and the Philippines to harden the Yonaguni Islands that stretch from the south of Japan to the north of Taiwan and the Batanes Islands that reach from the north of the Philippines to the south of Taiwan.

These Philippine and Japanese territories off Taiwan’s coast are particularly valuable entry points because of the Ryukyu Trench and the Philippine Sea Plate which provide easy access to the Pacific Ocean. If Taiwan falls to China, the US and its Pacific allies should already be in a position to plan for the next phase of China’s aggression as it will not stop with Taiwan.

If the US, together with the Philippines and Japan, fail to fortify these strategic island networks, American Pacific power will be pushed back to Hawaii. Allies will also face an authoritarian and mercantilist regional order that they do not wish to see return. China can be contained, but the time to act is now.

Alexis Littlefield, PhD, is Chief of Staff at the National Institute for Deterrence Studies and a Fellow of the Institute. He lived in Taiwan and China for two decades. Views expressed in this article are the author’s own.

Increasing the Archipelagic Defense from the Philippines to Japan was originally published on Global Security Review.