Arming U.S. Navy Hospital Ships?
Is it time to rethink how U.S. Navy hospital ships are armed? Recent naval warfare in the Red and Black Seas highlights the potential vulnerability of surface ships to remote attacks by missiles and drones. These ships could include military hospital ships, which are granted special protections under the law of armed conflict (LOAC) because of their exclusively humanitarian function of providing assistance impartially to the wounded, sick, and shipwrecked during armed conflict.
By way of context, the 1949 Geneva Convention for the Amelioration of the Condition of Wounded, Sick and Shipwrecked Members of the Armed Forces at Sea (GC II) defines military hospital ships as surface “ships built or equipped by the Powers specially and solely with a view to assisting the wounded, sick and shipwrecked, to treating them and to transporting them” (GC II, art. 22). Hospital ships “may in no circumstances be attacked or captured, but shall at all times be respected and protected” (GC II, art. 22). The prohibition on attacks includes not only physical acts of violence but also cyber attacks designed to result in damage, destruction, injury, or death (Newport Manual, p. 191-92).
A recent Navy Times article questioned whether U.S. Navy ships should be armed to protect themselves. Relying, in part, on a paper published in the journal Military Medicine, the Navy Times article raised the issue of whether the modern threat environment increases hospital ships’ need for additional defensive measures. The issue of more robust defensive means on U.S. Navy hospital ships is ripe for consideration for several reasons. First, the targeting of hospitals and medical personnel has been and continues to be a fact in modern armed conflicts. Notwithstanding the special protections for healthcare providers and facilities under LOAC, the grim reality is that attacks on medical facilities, healthcare personnel, and the patients they serve are too common and increasing. Second, sweeping technological changes since the 1949 Geneva Conventions have made hospital ships more and more vulnerable to such means and methods of warfare, such as long-range missiles, drones, and high-speed surface craft, among many others. Third, the U.S. Navy is ordering three new expeditionary hospital ships, making this an opportune time to consider what, if any, additional defensive armaments should be incorporated into the new class of hospital ships.
This post will briefly discuss the history and importance of military hospital ships, highlight several critical LOAC provisions on military hospital ships, discuss how military hospital ships are currently armed, and conclude with some thoughts about how they could and should be armed to defend themselves in the future. While the hospital ships used by National Red Cross/Red Crescent Societies, officially recognized relief societies, or private persons have the same legal protection as military hospital ships (GC II, art. 24), this post focuses solely on the LOAC issues related to the arming of military hospital ships.
Hospital Ships – Yesterday and Today
A military hospital ship is, in essence, a floating trauma center with a history extending to ancient times. During the 18th and 19th centuries, ships accompanied naval forces, often deployed near the coast of territories where fighting was taking place, to collect, treat, and transport the wounded and shipwrecked (International Committee of the Red Cross (ICRC), 2017 Commentary on GC II, para. 1929). The U.S. Navy recognized the need for hospital ships early in its history with the designation of a captured two-masted sailing vessel named the Intrepid in the fight against the Tripolitan pirates in 1803. During the American Civil War, the U.S. Navy converted the USS Red Rover into a hospital ship and treated more than 2,000 wounded and sick soldiers and sailors on both sides of the conflict.
Hospital ships were used on a significant scale during the First and Second World Wars. In the First World War, hospital ships were used primarily to transport the sick and injured from the theater of operations. By contrast, in the Second World War, their use depended on who was using them, with the Army and the Navy operating them for different purposes. Navy hospital ships were fully equipped hospitals designed to receive casualties directly from combat. Army ships were designed and equipped to evacuate patients to hospitals in rear areas. Today, the U.S. Navy’s Military Sealift Command operates the USNS Mercy and Comfort. The USNS Mercy and Comfort, each with 1,000 hospital beds, 11 operating rooms, and an extensive array of medical and dental capabilities, provide afloat, mobile, acute surgical medical facilities.
Regarding defensive capabilities, according to the recent Military Medicine article on arming hospital ships, “U.S. Navy doctrine historically prohibited the possession or use by hospital ships of weapons that could be used as offensive weapons . . . [and until] recently hospital ships only had tools such as fire hoses, flares, side arms, and rifles for self-defense” (p. e111). In deployments in more recent times, the Navy has installed machine guns on hospital ships, recognizing a changed threat environment (p. e111).
Hospital Ships and LOAC
Article 1 of the 1899 Hague Convention (III) provides,
Military hospital ships, that is to say, ships constructed or assigned by States specially and solely for the purpose of assisting the wounded, sick or shipwrecked, and the names of which shall have been communicated to the belligerent Powers at the beginning or during the course of hostilities, and in any case before they are employed, shall be respected and cannot be captured while hostilities last.
At the Second Hague Peace Conference in 1907, the delegates did not find it necessary to substantially modify Article 1 and adopted an almost identical provision in the 1907 Hague Convention (X) (Hague Convention X, art. 1). Even with the expressed and enhanced legal protection for hospital ships outlined in the 1899 Hague Convention (III) and the 1907 Hague Convention (X), State practice during the First and Second World Wars highlighted the necessity of clarifying and developing LOAC protections for hospital ships (ICRC, 2017 Commentary on GC II, para. 1934).
Articles 22 to 35 of GC II address hospital ships. There are several key provisions relevant to the protection and arming of hospital ships. First, as noted in the 2023 Newport Manual of the Law of Naval Warfare, the obligations arising under GC II to respect and protect hospital ships at all times implies not interfering with or preventing them from performing their humanitarian functions (p. 192). Second, military hospital ships must be painted white and display the emblem of the Red Cross (or Red Crescent or Red Crystal) on the hull and horizontal surfaces (GC II, art. 43). Third, during an international armed conflict, the protection of hospital ships is dependent on the condition “that their names and descriptions have been notified to the Parties to the conflict ten days before those ships are employed” (GC II, art. 22). Fourth, belligerents are prohibited from using hospital ships for any military purposes, including hampering the movement of combatants (GC II, art. 30). As noted by the Newport Manual, “[t]his prohibition is not limited to the gathering of information, the carriage of dispatches, or the transportation of troops, arms, and munitions, but applies to any use of a military nature or that is of military value, such as hydrographic surveys” (p. 195).
In terms of loss of protections, Article 34(1) of GC II provides, in part, as follows:
The protection to which hospital ships . . . are entitled shall not cease unless they are used to commit, outside their humanitarian duties, acts harmful to the enemy. Protection may, however, cease only after due warning has been given, naming in all appropriate cases a reasonable time limit, and after such warning has remained unheeded.
Importantly, Article 35(1) of GC II clarifies that the fact that hospital ship crews are armed for their own defense and that of the wounded and sick is recognized as a condition that does not deprive a hospital ship of its protected status. Similarly, Article 22 of the first Geneva Convention also permits the personnel of medical units and establishments on land to be armed for their own defense or that of the wounded and sick.
The Newport Manual specifically highlights the controversy surrounding arming hospital ships. It notes that for a long time, arming hospital ships was recognized as incompatible with their humanitarian functions. Thus, anything beyond small arms carried by the crew and, of course, those taken from the wounded, sick, and shipwrecked, would result in the loss of protection for the hospital ship (p. 199).
Recognizing that purely deflective means such as chaff or flares were not sufficient to effectively defend against terrorist, suicide, or other illegal attacks, during the 2003 Iraq War, .30-caliber and .50-caliber machine guns were employed on the USNS Comfort to defend it against the threat of explosive laden small-craft vessels (p. 199). The Newport Manual takes the position that,
since no State party to GC II protested those measures, it is safe to conclude that they have acquiesced in the U.S. practice. Accordingly, it is permissible to equip hospital ships with machine guns and other defensive weapons if there are reasonable grounds for assuming that, in the circumstances ruling at the time, their protected status will be disregarded by the enemy or by non-State actors (p. 199-200).
Defending Hospital Ships: The Legal and the Practical
Although the Newport Manual concludes that, as a matter of customary international law, arming hospital ships with “machine guns and other defensive weapons” is permissible when circumstances reasonably indicate the hospital ships could be unlawfully targeted, it does not clarify what “other defensive weapons” might be lawfully employed on a hospital ship (p. 199-200). While the machine guns employed on U.S. hospital ships during the war on terror are potentially effective at defending a hospital ship against small-craft threats like that used to attack the USS Cole, hospital ships face many other threats on the modern maritime battlefield.
Recent Houthi attacks in the Red Sea have been primarily conducted with missiles and drones, against which machine guns are much less effective. The relatively small size and high speed of incoming missiles make it difficult for a person shooting a machine gun to detect and engage such threats. While drones are often a slower moving threat, the ability to use multiple drones at the same time can easily overwhelm a person firing a machine gun.
For many years, the Navy has used the MK 15 Phalanx Close-In Weapon System (CIWS), which in its most recent variation is capable of countering close-aboard missile, drone, and small high speed surface craft threats. The CIWS defensive weapon system relies on an advanced radar system capable of detecting, tracking, and engaging incoming missile or drone threats automatically, making it a natural weapon system to consider for protecting hospital ships from missile and drone attack. The system fires a 20-millimeter round at up to 4,500 rounds per minute. A CIWS system is not capable of being employed in offensive naval operations, as it has a limited range due to its function as a last-ditch missile defense.
Although the effective range of CIWS remains classified, recent reporting about the use of CIWS against Houthi attacks stated that CIWS engaged an incoming missile that got as close as 1 mile from the warship, much closer than the reported ranges of other missile-based anti-missile weapons carried onboard many U.S. warships, such as the SM-2 and SM-6. Thus, a CIWS system is a clear example of a defensive weapon system that, in the context of countering increasingly likely missile and drone threats, constitutes a reasonable extension of the emerging customary international law supporting a minimal level of defensive weaponry for hospital ships.
Other standard defensive weapons systems, such as the Navy’s SM-2 and SM-6 missile systems, are even more effective at countering missile threats, but employing them onboard the new class of hospital ship would be an overbroad application of the Newport Manual’s permissive allowance for defensive weaponry. The CIWS has the virtue of being relatively unimposing, having a limited range, and firing bullets, which keep it somewhat close to the historical tradition of permitting the employment of small arms for self-defense. Missile systems lack some or all of these characteristics, as they have an often extended range (up to 200 nm for some variants) and carry explosives. This makes anti-missile missile systems much more likely to be considered as aggressive rather than mere self-defense weaponry. If the CIWS is akin to the small arms permitted to protect the crew and patients of early hospital ships, modern anti-missile missile systems are more akin to the deck guns which treaty drafters were eager to keep off hospital ships.
Additionally, the complexity, cost, and crew-manning requirements associated with adding more sophisticated weaponry provide a policy reason to limit any additional self-defensive armaments for hospital ships to the CIWS or similar systems. Any anti-missile or anti-drone weapon system will require space for ammunition or missiles, additional supporting systems such as specialized radars, and additional crew members to maintain and operate the systems. The reliance of SM-2 and SM-6 missiles on the AEGIS weapon system would require more substantial design modifications and many more sailors to maintain and operate than a CIWS system that is capable of operating without AEGIS. Thus, in addition to the likely legal limitations on placing anything more advanced than an MK-15 CIWS on the new class of hospital ships, important cost and design considerations argue against deploying more advanced missile-based anti-missile weaponry.
Concluding Thoughts
Hospital ships serve a vital humanitarian function and are entitled to extensive protections under LOAC. To allow these vessels to continue to perform their important tasks on today’s oceans, it is essential to equip them with self-defense capabilities to the full extent of the law. While early interpretations of what defensive armaments were permissible on hospital ships were limited to small arms for personnel protection, emerging trends in State practice indicate that arming hospital ships with a minimal yet effective means of self-defense against reasonably likely attacks does not forfeit their protected status.
In a world where missile and drone attacks are increasing from not only States but also non-State armed groups, it is lawful to employ systems such as the CIWS as a reasonable and limited means of self-defense for hospital ships. More advanced anti-missile weaponry is likely not necessary to counter these threats and may add unnecessary cost and complexity to hospital ship design and manning. Therefore, using them onboard hospital ships should be avoided.
***
Brigadier General (ret.) David A. Wallace previously served as the Professor and Head, Department of Law, United States Military Academy, West Point, New York, and has been designated a Professor Emeritus. He is currently the United States Naval Academy Class of 1971 Distinguished Military Professor of Law & Leadership.
Lieutenant Commander Christopher J. Hart is a submarine officer stationed at the United States Naval Academy as a master instructor in the Leadership, Ethics, and Law Department.
The views expressed in this work are those of the authors. They do not necessarily reflect the official policy or position of the United States Naval Academy, United States Military Academy, the Department of the Navy, the Department of the Army, or the Department of Defense.
Photo credit: Mass Communication Specialist 3rd Class Michael Feddersen
