The Chilean Marine’s contribution to coastal defense operations is tactically obsolete and does not take advantage of the national insular territory in the Pacific. Current theory suggests the defensive campaign concept involves operations in three spaces: in-depth, the Navy and Air Force seek to interdict the enemy fleet; at the water’s edge, Marines’ coastal artillery units pursue the disruption of ship-to-shore movements; in the rear, a mobile defense is prepared to contain and counterattack adversary forces that have managed to disembark. Aerial tactical connectors have reduced the importance of suitable landing beaches, making it difficult to foresee the landing area for disembarking. Ship-to-objective maneuver (STOM) and over-the-horizon (OTH) movement have rendered the artillery defense outdated, allowing tactical connectors to depart beyond the defense weapons ranges. In addition, Marine’s defensive concept is focused on the continental area of the country, exposing critical coastal infrastructure and civilian population to military actions, simultaneously generating a permissive environment for an adversary’s seizure of islands that could constitute expeditionary advance bases (EABs).

This problem is not merely tactical. The Chilean national defense policy defines the Pacific as a vital zone for the country’s development, recognizing that conflicts and potential risks can directly affect national security (Ministerio de Defensa Nacional, 2020). Therefore, Chilean Marine’s defensive systems must line up with national interest. A suitable and feasible solution is possible in the short term. The Chilean Navy has long-range anti-air and anti-surface missile capabilities, potentially replicable to ground units. The latter turns into the chance to transform the obsolete defense systems into a long-range missile concept. In that sense, the Chilean Marine Corps should implement mobile Anti-Access/Area Denial (A2/AD) nuclei to deny adversaries’ attempts to conduct a joint forcible entry from the sea, defeating surface and air threats before reaching the coast or potential EABs, increasing the national air and surface superiority against a possible peer adversary.

Currently, the coastal defense systems used by the Chilean Marine Corps present significant limitations to oppose forces capable of executing STOM and OTH movements. The principal assets of the defensive system are M-71 155/39 mm howitzers. Since batteries range does not exceed 16 nautical miles (nm), enemy amphibious ships may maintain a safe distance from coast-departing tactical connectors without opposition. Using OTH movements, assault waves can depart at 25 nm from the coast (Jerome,Thomas, n.d.), nullifying the batteries´ ability to target them at this distance. Additionally, the employment of rotary wing assets enables insertion beyond 25 nm allowing enemy amphibious assets optimal protection from the coastal defense artillery units. The actual defense system does not include anti-air capabilities that can neutralize aerial tactical connectors, an exploitable vulnerability from an enemy aviation perspective. Consequently, the Marines Corps does not possess the capability to disrupt the modern amphibious fleet and is easily neutralized by a peer/near-peer adversary.

Second, the Marine coastal defense units are geographically limited in the continental territory, with the exception of close-to-shore islands in the southern portion of the country. More specifically, the current system cannot defend beyond the water’s edge. The employment of helicopters or tiltrotor aircraft enables landings on 70% of the world’s coastline (Gatchel,1996), making defense at the water’s edge impractical, less for the longest country in the world. The actual location is not only ineffective but dangerous. Chile possesses a coastline of 6,435 km, and its average width is 180 km; therefore, most of its population lives near coastal areas. The position of the Marine coastal defense systems allows a potential adversary the space to target populated civilian territory, increasing potential collateral damage during combat operations. Regarding instruments of national power, Chile moves more than 95% of its economy through the Pacific. Locating the coastal defense units near the continental area allows the adversary to target ports, representing critical logistic infrastructure to the country. Chile cannot afford to put its population or economic capacity at risk in a possible conflict scenario; damage to port infrastructure would strangle the national economy, making further war efforts impossible.

Third, Chile has islands that represent potential EABs, and none of them have defensive measures to deny an assault from the sea. Easter Island, the Juan Fernandez Archipelago, and San Felix Island are within the sovereign islands of Chile in the Pacific, representing possible staging points for a subsequent invasion. Recovering an island in a future conflict will have a significant cost for Chile. For example, in 1982, the United Kingdom had to invest 4 billion pounds in recovering the Falklands/Malvinas islands (Privratsky,2014). Increased investment in the island’s protection could have deterred or denied the Argentinian invasion without requiring a Joint Task Force of close to 10,000 personnel (Ibid). Therefore, the effort to recover an island would represent almost two points of Chile’s GDP, which is preventable with the evolution of the current coastal defense system to an A2/AD concept located within the insular and continental territory.

The future location of the systems could be far removed from the continent, generating depth to the defense, isolating population, and critical infrastructure from the conflict. The concept will evolve into an A2/AD system capable of neutralizing enemy transport units on their approach to the coast. Simultaneously, it will deny the seizure of islands that could serve as EABs to potential adversaries.

Regarding range and capabilities, the artillery coastal defense system will mutate into a missiles model, denying access to the surface and air units to a determined area of operations. Each nucleus will have the ability to neutralize enemy surface units at no less than 100 nautical miles using Exocet MM 40 Block Three missiles already existing in the Chilean Navy. To supplement the anti-air shortfall, the nuclei will be able to neutralize enemy air units at no less than 25 kilometers using the Common Anti-air Modular Missile, also existing in the Chilean surface units. Transferring the capabilities mentioned above to Marine units is possible. MBDA, the manufacturer of both missiles, offers its in naval assets and ground units (MBDA,2022). Using existing technology, private support, and the Navy’s shipyards and workshops (ASMAR), weapons will adapt to Marines´ employment. Therefore, the evolution of current coastal defense systems to A2/AD will provide the anti-surface and anti-aircraft capability needed to efficiently oppose a peer adversary’s attempt to conduct a joint forcible entry from the sea, without requiring a budget increase.

The targeting process will change from a water´s edge focus to a mass fires focus while the enemy Task Force is still in its moving phase. Considering that an expeditionary force is of little value until it manages to land (Gatchel, 2016), with the missile capability, the defense will center on detecting and neutralizing the expeditionary forces center of gravity: amphibius and logistics ships (Ibid). In coastal defense, prioritizing targets and defense resources is particularly important. During the Argentine defense of the Falklands/Malvinas, the navy used most of its Exocet missiles on surface units, producing no decisive effect on the British assault. A single missile was used against a logistics unit destroying 75% of the British CH-47s, forcing them into a winter ground campaign (Privratsky,2014). The A2/AD will deny the adversary’s intentions even before being able to execute STOM or OTH, concentrating on the factors that sustain the force, making a subsequent landing unfeasible.

In solving the EABs problem, the defensive nuclei will be capable of operating in the island territory. The exact location and quantity of the nuclei will depend on the analysis of a potential enemy during the strategic and national planification process. However, the systems should be located over islands within the national territory, generating possibilities to establish defensive surfaces between the coast and Easter Island, creating a potential defensive depth of 1,997 nm. Landmasses with the capacity to operate with ships and heavy aircraft (i.e., San Felix, Easter Island, Navarino Island, and the Juan Fernandez Archipelago) can transform into active defense systems denying their use as an EAB for the enemy. Even if the adversary prefers a direct approach to the continent, the defense will provide 100 nm fire perimeters that would canalize him to potential joint surface missile areas. The new concept of location will solve two problems simultaneously: a) population and critical infrastructure will maintain outside the engagement zone, and b) islands will constitute defensive surfaces instead a permissive EABs.

By the Naval-Surface community perspective, many may argue that to protect the national territory from adversary joint forcible entry from the sea a more logical solution is to merely increase the size of the fleet. However, in this case, the latter is neither feasible nor convenient. Chile has an exclusive economic maritime zone of 3,150,739 km2; protecting it with only warships is not viable in monetary terms. Regarding human resources, an A2/AD system deployed on an island can even be operated remotely, like the NMESIS system, a joint Navy-Marines anti-surface missile, reducing human costs significantly and de-stressing the budget.

Regarding convenience, the fleet cannot remain in a defensive condition. Disrupting the adversary sea power (bases, merchants, and the enemy´s navy), seeking a resolution in the shortest time should be the priority. The way to achieve resolution is through offense (Clausewitz,1976), above all in naval warfare, where first strike is essential (Hughes and Girrier, 2018). In addition, to protect island territory, it is indispensable to be capable of resisting kinetic actions, maintaining the defensive posture. Given the possibilities of concealment and protection offered by the terrain, an A2/AD nuclei can support more attrition instead of combat ships that can be neutralized by a single impact (Ibid). The desired effect is the capability to simultaneously conduct sea denial and sea control operations. Defensive nuclei and surface units will complement each other, creating an operational model capable of protecting the national territory, and ultimately allowing time/space while seeking resolution through joint offensive actions.

The Marine Corps´ coastal defense concept and capabilities must adapt to modern amphibious warfare. Defense at the water´s edge is not a convenient option, especially for the longest country in the world. The batteries do not possess the capabilities to oppose OTH movements and are less capable of denying a peer adversary able to execute STOM using tactical air connectors. The A2/AD system is a feasible adaptation process that will increase Chiles’s national sea power in the region. Adapting naval capabilities to Marine units will provide defensive assets with the capacity to neutralize surface units at 100 nm and destroy air targets at 25 kilometers, becoming a relevant deterrent for any potential adversary. The A2/AD nuclei will generate depth to the coastal defense system, maintaining population and critical economic infrastructure out of the engagement area. Simultaneously, the new concept will permit the direct protection of national islands in the Pacific, denying its employment as EABs. With the joint capability’s integration, the proposed A2/AD Marines nuclei will severely increase the country’s air and surface superiority against a peer adversary’s attempt to conduct an invasion through the sea. Chile has no declared enemies, which does not mean it is a country exempt from conflict. The situation in the Pacific is uncertain, and Chile aspires to maintain its sovereignty and maritime communications lines open for the nation’s sustenance. For this reason, relevant defensive systems are essential in the most critical area of maneuver, the sea.