Geography does not only define what must be defended. It assigns roles to every instrument of national power.

In an archipelago, the conventional instinct is to look seaward — and rightly so. Maritime domain awareness, coastal missile batteries, naval patrols, and air defense networks are the visible expression of Philippine strategic intent in the West Philippine Sea. The CADC’s logic is sound: an island nation that cannot control its surrounding waters cannot control its fate.

But there is a prior question that strategic discourse tends to skip: who holds the islands themselves?

Every maritime chokepoint the Philippines must defend — the Luzon Strait, the Sibutu Passage, the Mindoro Strait — is flanked by land. Every logistics node that sustains forward naval and air operations sits on land. Every coastal community whose cooperation determines whether a maritime awareness network functions is a land-based population. Every EDCA facility that anchors allied deterrence requires perimeter security, access control, and surrounding community stability — all land force responsibilities.

Robert Kaplan’s warning in The Revenge of Geography (2012) is usually read as a maritime argument. For the Philippines, it is equally a land argument: the islands themselves are the geography. And islands that are insecure, ungoverned, or disconnected from the state are not strategic assets — they are liabilities.

The AFP’s ground forces are not a secondary instrument in archipelagic defense. They are its enabling layer.

Consider what the land defense force actually secures in a contested archipelago scenario. Forward operating bases and EDCA facilities require ground security forces — not simply for protection against conventional attack, but against gray-zone harassment, sabotage, and the kind of low-intensity interference that an adversary can plausibly deny. A coastal missile battery without a secure perimeter is an expensive target. A pre-positioned fuel depot without force protection is a vulnerability, not an asset.

Milan Vego’s framework in Joint Operational Warfare (2009) is instructive here: space, time, and force are the fundamental operational variables. In the Philippine archipelago, the land force’s role is to master the space dimension — to ensure that the physical terrain from which maritime and air operations project remains under Philippine control, accessible, and sustainably defended.

This is not a new insight for practitioners. It is, however, an insight that gets lost in strategic discourse dominated by naval procurement debates and maritime incident coverage. The BrahMos coastal battery receives public attention. The ground force that secures the installation it sits on does not.

Strategy is a logistics problem. And in the Philippines, logistics is a land problem before it is a maritime one.

Three compounding vulnerabilities stand out — and all three are fundamentally anchored on land. Port concentration: over 60 percent of commercial maritime traffic moves through Manila, Cebu, and Davao — three nodes whose ground security, access routes, and surrounding civil stability determine whether the fleet can be sustained at all. Energy infrastructure: petroleum storage facilities, pipeline networks, and fuel depots are land-based systems whose protection falls to ground forces and civil-military coordination. And pre-positioned stocks at EDCA sites — the dispersed sustainment architecture that extends operational endurance across the archipelago — are only as reliable as the ground security and LGU relationships that surround them.

The BRP Sierra Madre’s resupply missions are frequently analyzed as a maritime challenge. They are equally a land logistics challenge: the vessels that resupply Ayungin Shoal depart from Philippine ports. Those ports require functioning ground infrastructure, secure access, and a stable civil environment. Disrupt the land side of that equation and the maritime mission fails before a single Chinese vessel intervenes.

Here is what distinguishes the land defense force’s contribution from every other instrument in the archipelagic defense architecture: only the Army lives among the people.

Ships patrol waters. Aircraft cover airspace. But the ground force is present in the barangay, the municipality, and the province — day after day, through peace and crisis alike. That persistent presence is not merely a security function. It is the mechanism through which the state builds or loses the population trust that determines whether a defense strategy is sustainable across years and administrations.

Andrew Lambert’s argument in Seapower States (2018) that maritime nations must cultivate maritime consciousness — an identity rooted in the sea — points directly to a land force function. That consciousness is not built by admirals addressing audiences in Manila. It is built by soldiers and reservists present in coastal communities, by NSTP programs in municipal schools, by civil-military operations that connect LGUs to the broader defense architecture, and by disaster response that demonstrates the state’s reliability when communities are most vulnerable.

The Philippines has more than 800 coastal municipalities. Each one is a potential node in a whole-of-nation maritime awareness network. Each one has a barangay captain, a local government unit, a school, a health center, and a community that either trusts the state or does not. That trust is built or eroded at the ground level — and the ground force is the instrument that most directly shapes it.

The CADC envisions the entire archipelago as an integrated operational theater. But integration does not happen at the doctrinal level alone. It happens at the LGU level, in the coordination between municipal mayors, barangay captains, AFP reserve units, PNP stations, DRRM councils, and community volunteer networks.

This coordination architecture is the land force’s institutional responsibility. Republic Act 7077 — the Citizen Armed Force of the Philippines Act — and Republic Act 10121 — the DRRM Act — both embed AFP ground force roles in local governance and disaster response structures. The Retooled Community Support Program and civil-military operations doctrine recognize what strategic analysts sometimes overlook: that the most consequential terrain in an archipelagic defense is often not the sea between islands, but the relationship between the state and the community on each island.

When Typhoon Odette struck in December 2021, the communities that recovered fastest were not those with the most national government resources. They were those where pre-existing coordination between LGU officials, AFP reserve units, DRRM offices, and community networks meant that the first 72 hours did not have to be spent building relationships from scratch.

That pre-existing coordination is a land force product. It is built through presence, training, civil-military engagement, and the deliberate cultivation of relationships that function under pressure because they were established before pressure arrived. A maritime patrol cannot build it. An air sortie cannot sustain it. The ground force, present and trusted in the community, is the only instrument that can.

Japan’s investment in the Nansei Shoto island chain offers the most instructive regional comparison for Philippine land force doctrine. What Tokyo recognized is that defending an island chain requires holding the islands themselves with credible ground combat power, not merely patrolling the waters around them. Multi-domain radar systems, ground-based anti-ship missile batteries, and rapid-deployment ground forces work together — the maritime and air components project from positions that ground forces hold and sustain.

For the Philippines, the equivalent logic applies across the western island chain — from Batanes in the north through Palawan to the Sulu Archipelago in the south. Securing and sustaining those island positions is not primarily a naval or air force task. It is a ground force task. The Army holds the ground that the Navy and Air Force project from. That sequencing is not a hierarchy of importance — it is a description of operational dependency.

A nation whose interior is fractured cannot project credible resolve at its maritime frontier.

China’s gray-zone strategy in the West Philippine Sea is calibrated to test Philippine national will as much as Philippine military capability. The pressure is designed to be sustained, graduated, and patient — to erode resolve over time rather than defeat it in a single confrontation. Sustaining that resolve requires domestic cohesion: public trust in institutions, confidence in the state’s competence, and the social solidarity that makes a population willing to bear the costs of resistance.

Internal security challenges do not exist in a separate compartment from the West Philippine Sea contest. They compete for the same institutional bandwidth. They erode the same public trust. They create the same governance gaps that external actors can exploit through information operations, economic leverage, and political interference.

The land force’s role in maintaining internal stability is therefore not a distraction from archipelagic defense. It is its precondition. A Philippines that is resilient internally — where LGUs function, where communities trust the state, where the AFP’s legitimacy is intact — is a Philippines that can sustain external resistance.

The CADC’s aspiration is a networked, integrated national defense posture — the entire archipelago functioning as a single operational system. That aspiration requires a connective tissue that spans the military, government, private sector, and civil society. Only one instrument is positioned to build that connective tissue at the local level: the ground force.

The Army’s presence in communities, its institutional relationships with LGUs under RA 7077 and RA 10121, its role in disaster response, its reserve force structure, and its civil-military operations capability make it the natural integrating force for the whole-of-nation architecture the CADC envisions. Not because the Army commands civilians — it does not, and should not — but because sustained ground presence is the mechanism through which the defense architecture connects to the population it is meant to protect.

Maritime consciousness, as Lambert argued, is built from the community upward. NSTP programs that cultivate civic defense awareness in schools, LGU coordination councils that integrate early warning with community response, reserve force networks that extend AFP reach into municipalities too small to garrison — all of these are products of ground force engagement, built through the kind of persistent presence that no other instrument can replicate.

Geography is the Philippines’ defining strategic reality. The sea is its domain, the archipelago is its theater, and maritime power — rightly — sits at the center of national defense strategy.

But maritime power projects from land. Ships depart from ports. Aircraft lift from runways. Missiles are sited on promontories. Alliances are anchored at bases. And the population whose will must be sustained through years of gray-zone pressure lives in barangays, municipalities, and provinces — on ground that must be held, governed, and kept resilient.

The CADC is the Philippines’ most coherent strategic expression yet of a nation choosing agency over passivity. Its maritime and air components are essential and irreplaceable. But the land force is what makes those components sustainable: securing the nodes from which they project, building the community trust that sustains national resolve, partnering with LGUs to create the whole-of-nation architecture the concept demands, and holding the physical terrain that everything else depends on.

Four imperatives follow. First, explicitly recognize the land force’s enabling role in CADC implementation — in doctrine, in budget, and in public communication. Second, deepen Army-LGU coordination as a standing peacetime function, not an emergency improvisation. Third, invest in the reserve force and civil-military infrastructure that extends ground force reach to every coastal municipality. And fourth, treat internal resilience — community trust, governance capacity, social cohesion — as a national security metric alongside naval tonnage and air sortie rates.

The Balangay connected communities across the archipelago through shared purpose and shared sea. It needed navigators to find the way. But it also needed people to hold the oars, maintain the hull, and keep the community aboard.