Filling up the gap at the southern flank of the first island chain: The role of the Philippines’ Comprehensive Archipelagic Defense Concept

During President Ferdinand Marcos, Jr.’s first official visit to India, he candidly announced what several defense officials, analysts, and military officers had only privately discussed in the Philippines: “If there is an all-out war, we will be drawn into it. We will have to go into Taiwan and bring our people home.”

Firstpost Managing Editor Palki Sharma raised this query during an interview about how the Philippines will respond if China launches an armed invasion of Taiwan. President Marcos Jr. replied that the Philippines “cannot stay out if a conflict breaks out between China and Taiwan,” as his country would be pulled into this armed conflict to “protect 250,000 Overseas Filipino Workers (OFW)” earning their living in Taiwan. Several days later, after his arrival to Manila, he repeated what he announced while he was in Delhi: “To be practical about it, if there is confrontation over Taiwan between China and the United States, there is no way that the Philippines can stay out of it because of our geographical location.”

President Marcos Jr. repeated this statement in the face of the Chinese foreign ministry’s vicious objection to what he said about what the Philippines would do if China launched its expected armed and forceful unification with Taiwan. The President’s bold statement about the Philippines’ role in a Taiwan contingency reflects his nation’s concern about the fate of hundreds of thousands of Filipinos working in this island republic. It also indicates his administration’s recognition of the tyranny of geography.

Located north of the Luzon Straits and the Bashi Channel, Taiwan is the Philippines’ closest neighbor. Historically, the Philippines has faced more existential security threats emanating from Taiwan. At the beginning of the Pacific War in December 1941, Japanese air and amphibious forces attacked the Philippines from Taiwan. Based in Taiwan, Imperial Army Japanese land-based bombers and fighters wiped out half of the United States Armed Forces in the Far East (USAFE) airpower at Clark Airfield and other airfields in Central Luzon. General Hisaichi Terauchi commanded the Imperial Japanese Army that launched the amphibious operations from Taiwan with four corps, landing at Batanes Islands in the middle of the Luzon Strait and on the tip of Northern Luzon. Both the Philippines and Taiwan are also part of the first island chain*.

THE GAP AT THE CHAIN’S SOUTHERN FLANK
The first island chain is the geopolitical linear arrangement of three major island groups: Japan/the Ryukyu Islands, Taiwan, and the Philippine archipelago. Recently, Chinese maritime expansion has challenged the US’ strategic position in the first-island chain from Japan to Taiwan to the Philippines. Projecting its growing comprehensive power westward, China seeks to break past the first island chain, namely Japan’s Ryukyu Island chain, Taiwan, and the Philippines, into the open waters of the Western and Central Pacific. Within this geopolitically confined island chain in the Western Pacific, China is conducting a massive naval build-up and operations aimed at pushing the US and neutralizing its allies over these contested island states, Japan, Taiwan, and the Philippines.

From China’s perspective, the Philippines is an attractive, appealing, and easy secondary spoil for its irredentist gambit next to Taiwan. Chinese analysts and strategic thinkers considered the Philippines a tail, a liability, and a vulnerability in the island chain. Chinese defense analysts and strategic thinkers disparaged the Philippines as the weakest link in the first island chain and a fair and easy target of its maritime expansion. For them, China must neutralize the Philippines as a necessary and significant step towards effecting sea control over the South China Sea and advancing beyond the first island chain. If given the opportunity, Beijing prefers Washington to abandon Manila as a treaty ally, thus effectively undermining American credibility with its more militarily capable Indo-Pacific allies such as Japan, South Korea, and even Taiwan.

FILLING THE GAP: THE CADC
In January 2024, Philippine Secretary of National Defense Gilberto Teodoro announced a new defense concept called the Comprehensive Archipelagic Defense Concept or CADC. Mr. Teodoro clarified, “CADC is about developing our (military capabilities) to protect and secure our entire territory and Exclusive Economic Zone (EEZ) to ensure that our people and all generations of Filipinos to come shall freely reap and enjoy the bounties of natural resources that are rightfully ours within our domain.”

This requires the Armed Forces of the Philippines (AFP) to create a credible defensive posture to build the country’s deterrent capabilities in the Philippines’ archipelagic waters and EEZ. The Philippine military must develop and enhance its maritime domain awareness, connectivity, intelligence capabilities (C41STAR), and area denial and deterrence capabilities in maritime and aerial domains.

The Marcos administration adopted the CADC, thereby accepting as a matter of national policy the long-drawn recognition within the national defense establishment and the AFP that China’s maritime expansion in the South China Sea poses an existential threat to Philippine national security.

The CADC requires the AFP to abandon its old 20th century concept of securing the country’s long and rugged coastal areas. This obliged the Philippine military to anticipate an invading force moving toward the country’s shoreline before mounting any combat operation against this amphibious enemy. Instead, the AFP is adapting to a new strategic paradigm to bolster its anti-access and area denial capabilities within the Philippines’ archipelagic territories, including its EEZ. These capabilities are aimed at preventing foreign navies from operating or crossing the vast stretches of its archipelagic territory, with the stated goal of making its EEZ in the West Philippine Sea/South China Sea a no-go zone for the Chinese maritime militia, the China Coast Guard, and People’s Liberation Army Navy.

The CADC’s long-term goal is to project the AFP’s capabilities to the Philippines’ 200-nautical-mile EEZ. These moves aim to bolster the Philippines’ diplomatic and strategic leverage against Chinese maritime expansion in the South China Sea. However, by implementing the CADC, the Philippines is also preparing to address another potential flashpoint in its immediate northern neighbor: Taiwan. The CADC would effectively enable the Philippines to fill the strategic vacuum in the southern flank of the first island chain.

*According to Wikipedia, “The first island chain is the first string of major Pacific archipelagos out from the East Asian continental mainland coast.” — Ed.

Renato Cruz De Castro, a Professor at De La Salle University, is a Trustee, Program Convenor, and Non-Resident Fellow at the Stratbase Institute.