Fort Drum Shows How States Can Push Back on China’s Maritime Aggression

The South China Sea is one of the most contested maritime areas in the world. Smaller countries like the Philippines, Vietnam, Malaysia, and Indonesia face increasing pressure from an assertive and militarily powerful People’s Republic of China due to overlapping sovereignty claims and critical trade routes. Beijing’s maritime power projection threatens regional sovereignty and economic rights under the U.N. Convention on the Law of the Sea through its militarization of artificial islands, aggressive maritime activities, and widespread illegal fishing. To address this imbalance, claimant states should adopt asymmetric strategies that improve maritime domain awareness, defend exclusive economic zones, and impose costs on unlawful actions. One such approach is the development of maritime outposts, inspired by the Philippines’ Fort Drum in Manila Bay.

Fort Drum: A Historical Model of Maritime Defense

Fort Drum, built by the United States in the early 20th century, stands as a lasting example of ingenuity in coastal defense from a bygone era. Located at the entrance of Manila Bay, engineers transformed El Fraile Island into a reinforced concrete battleship equipped with 14-inch coastal cannons and designed to withstand heavy bombardment. Although now conceptually outdated, Fort Drum’s resilience during World War II shows the potential of maritime outposts as operational deterrents against gray-zone activities. Accordingly, its legacy provides lessons for modern asymmetric defense in the South China Sea.

Asymmetric warfare aims to impose disproportionate costs on a stronger adversary using dissimilar techniques and capabilities to enhance strengths and mask disadvantages in unexpected ways. Rather than mirroring China’s military build-up, Southeast Asian states can develop layered defenses that leverage geography, low-cost technology, and irregular operations. Recent conflicts highlight the effectiveness of this approach: Ukraine’s innovative use of drone swarms and Azerbaijan’s deployment of loitering munitions in the Second Nagorno-Karabakh War both illustrate how smaller forces can offset conventional disadvantages. Using Fort Drum as an example, these outposts should be seen as methods to maintain presence and complicate adversary maneuvers, rather than static fortresses meant to withstand and repel a direct attack. Fort Drum was carved from an island and reinforced into a concrete battleship, built to withstand direct fire and serve as a lasting deterrent at the entrance to Manila Bay. Today, such maritime outposts can embody similar permanence, signaling sovereignty and deterrence in contested waters.