Some Thoughts on the Use of Land-Based Missiles for Maritime Denial

Eric Lindsey of CSBA published an excellent monograph last month examining how the U.S. Army might field land-based anti-ship missiles and rockets, not to mention air and missile defense systems, to defend forward U.S. allies from aggression. I strongly agree with the concept in principle. Such capabilities would be extremely useful for constraining an adversary’s wartime use of the waters and airspace adjacent to a U.S. ally’s territory. They would definitely increase the adversary’s potential costs and risks of hazarding transits through maritime chokepoints controlled by the ally, conducting close blockades against the ally, or executing amphibious/airborne assaults against the ally. They would provide valuable layers for defense-in-depth against an adversary’s attempts to strike forces and infrastructure located on the ally’s territory or in nearby areas at sea. They could certainly help with carving out temporary ‘pockets’ that support friendly air and naval operations within a contested zone.

There are a few key details, however, that I think require more analytical attention. First, the use of anti-ship missiles for over-the-horizon engagements depends upon scouting. Surveillance could be performed using land-based radiofrequency direction-finding systems or over-the-horizon radars, but neither can positively and confidently verify that a given contact is in fact something worth expending scarce missiles. Reconnaissance assets such as fishing boats, submarines, aircraft, or unmanned vehicles are better suited for the tasks of classifying contacts and cueing missile attacks, but this raises the question of whether their information would be processed through a fusion center that generates a shared situational picture for the entire defense or whether it would be provided directly to the missile units. There are advantages and drawbacks for each that ought to be weighed; my own preference is that missile units would be supported by dedicated scouts (example: light UAVs that are organic to those units) that can also provide their information to a shareable situational picture. All this says nothing of the challenges of preventing the adversary from detecting, interpreting, and exploiting the communications between scout and shooter. The bottom line is that looking at maximum missile ranges alone is insufficient; one must also consider maximum effective scouting range and networking architecture.

Second, while land-based missile systems do have some on-station endurance advantages over warships and aircraft, they are entirely dependent upon the security of the sea and air lines of communication that provide sustenance for their crews, repair parts, and replacement rounds. Hardened, peacetime-prepositioned stockpiles of materiel near these units’ operating areas can help with this, but during wartime these supplies will likely be consumed at a fast rate and certainly will not hold out any longer than they were sized to.

The lines of communications problem is less pressing for continental allies who, by virtue of territorial depth (or friendly neighbors), can access airfields and ports far from the adversary’s effective reach. However, this is a campaign-critical issue for defending allies who are not blessed with that strategic gift. As archipelagoes, Japanese and Filipino lines of communication are solely maritime. Given that they lie within a few hundred miles of continental Asia, their sea lines are inherently vulnerable to interdiction by submarines, and their airfields and ports are inherently vulnerable to aerospace bombardment. The situation is much the same with South Korea, a peninsular country whose hostile northern sibling denies it overland lines of communication. Taiwan’s circumstances should be self-explanatory.

Whereas China’s military clout is not yet sufficient to heavily degrade logistical flows to and then amongst the main Japanese and Philippine islands, there should be no illusions that these flows will be unpressured in a major war. The imposed degree of pressure would likely be greater on the margins for flows from Japan to South Korea. Flows from Japan (or from across the Pacific) to and amongst the central and southern Ryukyus could conceivably be at grave risk. I strongly support emplacing land-based defensive missiles in the Ryukyus as a means of reinforcing conventional deterrence, but unless these weapons are intended to be a wasting asset much more thought needs to be dedicated towards how they would be sustained throughout a protracted conflict. Lines of communication protection would be a central role for naval and land-based air forces; in a Western Pacific contingency it might be their most strategically important task in the aftermath of war initiation. I’ll be writing about this issue again in a few weeks.

Third, some thought needs to be dedicated towards when and how these missile forces would be deployed to the field. Using the Japanese example, let’s say the bulk of such forces were maintained in garrison in the main Japanese islands (or further to the rear in U.S. territories) for deployment to the Ryukyus only in a crisis. This would raise questions of whether crisis deployments could be done quickly and how the Chinese might interpret and react to such movements once they were detected. I would prefer permanent forward garrisoning of missile units on the islands they would be defending, but this would be not be inexpensive and would require significant political capital and resolve. Indeed, as is already evident with our existing forces in Okinawa, it might mean basing U.S. units in localities that may not be thrilled about serving as indefinite hosts.

None of this should be interpreted as hits against what I believe to be a very important tool for strengthening our extended conventional deterrence, and if necessary for defending embattled allies. I do believe, though, that if Army maritime missile force concepts are to gain the traction they deserve the issues above will need to be addressed.