Introduction
The sea is a special environment. For good reasons, the ships of all States enjoy freedom of navigation and other well-established rights, because their economies are highly dependent upon the use of the world's oceans. At the same time, coastal States enjoy various rights in the sea areas off their coasts, which they may enforce against foreign vessels, including by a use of proportionate force. Moreover, some coastal States have territorial and maritime claims that conflict or overlap with the claims of other States, and they are prepared to assert those claims by the use of their navies, coast guards or other State vessels. Again, such assertions may include aggressive operations sometimes amounting to what seems to be a use of force against the flag State of the vessels affected. It goes without saying that, at sea, there is an increased potential for tension and conflict.
Interference with foreign vessels or inter-State confrontations are not necessarily the rule, but they occur repeatedly. Hence, the question arises of whether and to what extent operations at sea qualify merely as “incidents at sea”, or as a use of force by one State against another State bringing an international armed conflict into existence. The present paper is an endeavour to provide criteria for an operable and reasonable distinction. It should be emphasized that although dealing with the concept of use of force, the paper merely addresses the jus in bello, not the jus ad bellum. Hence, the legality of the conduct under scrutiny according to any applicable international legal regime other than the jus in bello lies outside the paper's scope. Finally, the paper is based on the premise that a State's use of force against a foreign merchant vessel is presumed to be legal and, therefore, does not trigger the flag State's right of self-defence.Footnote 1
The present paper aims at a distinction between incidents at sea and situations that may trigger an international armed conflict. It will address the following questions: (1) Which State conduct directed against foreign warships and military aircraft qualifies as a use of force? (2) Does a use of force against merchant vesselsFootnote 2 or civil aircraft bring an international armed conflict into existence? (3) Can the use of civilian government agencies for purposes other than law enforcement qualify as a use of force bringing an international armed conflict into existence?
Distinction between international armed conflict and incidents at sea according to the updated ICRC Commentary of 2016
The position of the International Committee of the Red Cross (ICRC) regarding the definition of “international armed conflict” and its distinction from incidents at sea may be summarized as follows. The Commentary on Article 2 common to the four Geneva Conventions starts from the premise that the “determination of the existence of an armed conflict within the meaning of Article 2(1) must be based solely on the prevailing facts demonstrating the de facto existence of hostilities between the belligerents, even without a declaration of war”.Footnote 3 The characterization of a given situation by governments is irrelevant. Hence, an international armed conflict exists as soon as one or more States resorts to armed force against another State,Footnote 4 in particular when “classic means and methods of warfare … come into play”.Footnote 5 An international armed conflict may also come into existence “even if the armed confrontation does not involve military personnel but rather non-military State agencies such as paramilitary forces, border guards or coast guards”.Footnote 6 For the purpose of common Article 2(1), any use of force, irrespective of its intensity or duration, suffices;Footnote 7 as long as the “situation objectively shows for example that a State is effectively involved in military operations or any other hostile actions against another State, neutralizing enemy military personnel or assets, hampering its military operations or using/controlling its territory, it is an armed conflict”.Footnote 8
While the ICRC thus defines the concept of “international armed conflict” in a broad manner, it is not necessarily prepared to consider incidents at sea as a use of force bringing an international armed conflict into existence. One may not be prepared to accept the ICRC's reliance on an “objectivized belligerent intent”. This, however, is without relevance for the purposes of this paper, which deals not with ultra vires actions or actions resulting from mistakes but with actions that are either directed or endorsed by the respective government.
In sum, the ICRC seems to provide a clear and operable distinction between situations of international armed conflict and incidents at sea. However, in view of recent events it is worth taking a closer look at the conduct of States at sea.
Use of force against foreign warships and military aircraft
Use of traditional means and methods of warfare
According to the position taken here, the ICRC's position is correct insofar as a State's use of traditional methods and means of warfare against another State's warships or military aircraftFootnote 9 is concerned. There is no requirement of the target State responding by also resorting to a use of force. The most recent case of an international armed conflict – although of a short duration – having come into existence by the unilateral use of traditional means of warfare against a foreign warship is the sinking of the Cheonan.Footnote 10
On 26 March 2010, the South Korean warship Cheonan was hit by a torpedo, broke in half and sank. Forty-six South Korean sailors died. While the Democratic People's Republic of Korea (DPRK) denied responsibility, a multinational Joint Investigation Group concluded that the torpedo had been manufactured in the DPRK. A Multinational Combined Intelligence Task Force found that the torpedo had been launched from a DPRK submarine. The latter finding was confirmed by a Special Investigation Team established by the United Nations (UN) Command Military Armistice Commission, which considered the evidence to be “so overwhelming as to meet the … standard of beyond reasonable doubt”.Footnote 11 Still, the Republic of Korea did not respond by using force against DPRK warships or against DPRK territory. The ICC prosecutor, relying on the findings of the International Criminal Tribunal for the former Yugoslavia, the ICRC and legal writings, concluded that the “‘resort to armed force between States’ in the form of the alleged launching of a torpedo into the Cheonan … created an international armed conflict under customary international law”.Footnote 12 This finding of the existence of an international armed conflict is undoubtedly correct because a torpedo is a traditional means of warfare and the target was another State's warship.
Distinguishing “incidents at sea” from a use of force
The distinction between a resort to armed force, which brings into existence an international armed conflict, and measures which remain below that threshold is more complicated when States resort to a conduct that does not involve the use of traditional methods and means of warfare but that nevertheless may be considered aggressive or amounting to physical coercion – i.e., violence. The following cases show the varying degree of provocative conduct at sea that may or may not qualify as a use of force for the purpose of determining the existence of an international armed conflict. It needs to be emphasized that these cases are referred to solely for the purposes of illustrating the issues at stake. They may not be understood as an assessment of the legality of the respective conduct.
Examples of incidents involving warships and military aircraft
On 12 February 1988, USS Yorktown and USS Caron conducted freedom of navigation operationsFootnote 13 in the Black Sea approximately 7 to 10 nautical miles off the Crimean peninsula, within the territorial sea of (at the time) the Soviet Union. Soviet warships transmitted warnings to terminate the alleged violation of the “State borders of the Soviet Union” and then rammed the US warships, which were damaged, albeit not severely.Footnote 14
On 1 April 2001, a US Navy EP-3E reconnaissance aircraft was harassedFootnote 15 by People's Liberation Army Navy fighter aircraft at about 70 nautical miles off Hainan island, in international airspace. The harassment resulted in an accidental collision of a Chinese F-8II jet fighter and the EP-3E. While the Chinese aircraft crashed into the sea with the pilot lost, the US crew made an emergency landing of their damaged aircraft onto Hainan island. They were detained for eleven days.Footnote 16
In 2014, forty incidents involving Russian military aircraft occurred in the Baltic Sea area, some of which were of a “more aggressive or unusually provocative nature, bringing a higher level risk of escalation”.Footnote 17 In October of that year, Sweden conducted a search for a suspected Russian submarine in the sea areas off Stockholm.Footnote 18
In March 2015, Russian fighter jets used two NATO warships in the Black Sea as simulated targets in training exercises.Footnote 19 A similar incident occurred in the Black Sea on 12 April 2016, when a Russian military aircraft conducted simulated attacks on USS Donald Cook. In April 2016, a Russian jet harassed a US Air Force surveillance aircraft over the Baltic Sea, conducting a dangerous manoeuvre that came within 50 feet of the US aircraft's wings.Footnote 20
On 17 June 2016, Japanese military aircraft interceptedFootnote 21 two Chinese fighter jets over the East China Sea. Allegedly, the Japanese aircraft released infrared jamming shells and locked their fire-control radar on the Chinese aircraft.Footnote 22
Provocative/aggressive conduct or resort to armed force?
According to the ICRC Commentary, “even minor skirmishes between the armed forces, be they land, air or naval forces, would spark an international armed conflict and lead to the applicability of humanitarian law”.Footnote 23 This does not, however, mean that any form of physical coercion by a warship or military aircraft against foreign warships or military aircraft will qualify as a use of force resulting in an international armed conflict.Footnote 24 Arguably, the intentional ramming of a foreign warship, which occurred in the Black Sea in 1988, is an act of violence by the use of a traditional means of warfare – i.e., a warship. Seemingly, there is no difference between shots being fired and ramming because both are designed, or may reasonably be expected, to cause damage or even injury and death. The ICRC is seemingly not willing to share this conclusion, because the Commentary refers to numerous maritime incidents that involved various degrees of physical coercion, including the use of guns, and that are not considered as having created a situation of international armed conflict.Footnote 25 However, in none of the cases quoted was physical coercion applied against a foreign warship. Therefore, the situations referred to merely qualified as measures enforcing coastal States’ rights under the law of the sea or the applicable domestic law. Moreover, the ramming was undertaken with a view to hampering another State's military operations at sea, which, according to the ICRC Commentary, is a military operation bringing into existence an international armed conflict, if it is endorsed by the State concerned.Footnote 26 Nevertheless, it would seem odd to hold that the ramming, which is also referred to as the “Black Sea bumping incident”, initiated an international armed conflict between the U.S. and the Soviet Union because neither of the two States would have publicly drawn that conclusion. Obviously, the ramming, although an act of violence, did not pass the threshold necessary for qualifying as a use of military force.
Neither did the 2001 EP-3 incident trigger an international armed conflict – at least insofar as the damage inflicted to the aircraft is concerned. Supposedly, the Chinese aircraft were on an official mission aimed at harassing the US aircraft. The Chinese conduct resulted in severe damage to the EP-3 and the loss of a Chinese pilot. Seemingly, the use of force was sufficient to have initiated an international armed conflict between the United States and the People's Republic of China (PRC). However, the Chinese acts did not amount to armed conflict because they were the result of a mistake. Obviously, the harassment, albeit seriously dangerous, was not designed to damage or down the US aircraft. As rightly emphasized in the ICRC Commentary, the existence of an international armed conflict is not determined by acts “done in error” or by “situations that are the result of a mistake or of individual ultra vires acts, which – even if they might entail the international responsibility of the State to which the individual who committed the acts belongs – are not endorsed by the State concerned”.Footnote 27 These findings are without prejudice to whether the detention of the EP-3 crew following the emergency landing on Hainan island can be considered as having brought into existence an international armed conflict.
In contrast, an unconsented-to military operation in the territory of another State that is undertaken with the approval of the flag State “should be interpreted as an armed interference in the [coastal State's] sphere of sovereignty and thus may be an international armed conflict under Article 2(1)”.Footnote 28 Accordingly, the intentional presence of a foreign submarine operating submerged in the internal waters of another State without that State's consent could qualify as a use of force bringing into existence an international armed conflict. This situation should not be confused with a mere violation of Article 20 of the 1982 UN Convention on the Law of the Sea (UNLCOS) by a foreign submarine not navigating on the surface and not showing its flag.
It follows from the foregoing that certain military operations against foreign warships or military aircraft do not constitute a use of force, although they are provocative or aggressive in nature because they are neither intended nor expected to directly result in damage or injury. The same holds true if they in fact, but mistakenly, result in damage or injury. State practice provides sufficient evidence that there are certain actions which are to be strictly avoided because they have the potential of escalating a given situation, but which do not as such bring an international armed conflict into existence.
In 1972, the Soviet Union and the United States concluded an agreement aimed at the prevention of incidents at sea.Footnote 29 In 1989, the two States concluded a similar agreement on the prevention of dangerous military activities.Footnote 30 On 9/10 November 2014, the United States and the PRC concluded a Memorandum of Understanding on Rules of Behaviour for the safety of air and maritime encounters.Footnote 31 All these agreements are more or less identical with regard to the following military operations that are to be avoided:Footnote 32
• Simulation of attack by aiming guns, missiles, fire-control radars, torpedo tubes, or other weapons in the direction of military vessels or military aircraft encountered;Footnote 33
• Except in cases of distress, the discharge of signal rockets, weapons, or other objects in the direction of military vessels or military aircraft encountered;
• Illumination of the navigation bridges of military vessels or military aircraft cockpits;
• The use of a laser in such a manner as to cause harm to personnel or damage to equipment onboard military vessels or military aircraft encountered;
• Aerobatics and simulated attacks in the vicinity of vessels encountered;
• The unsafe approach by one Side's small craft to another Side's vessels; and
• Other actions that may pose a threat to the other Side's military vessels.Footnote 34
Unless required to maintain course and speed under the rules of the road,Footnote 35 ships operating in proximity to each other “shall remain well clear to avoid risk of collision” and shall avoid manoeuvring “in a manner which would hinder the evolution of the formation” of foreign ships.Footnote 36 Furthermore,
[s]hips engaged in surveillance of other ships shall stay at a distance which avoids the risk of collision and also shall avoid executing maneuvers embarrassing or endangering the ships under surveillance. Except when required to maintain course and speed under the Rules of the Road, a surveillant shall take positive early action so as, in the exercise of good seamanship, not to embarrass or endanger ships under surveillance.Footnote 37
Although dangerous and to be avoided under the respective agreements, manoeuvring in close proximity to other vessels and harassment or illumination of foreign warships and military aircraft do not qualify as a use of force bringing an international armed conflict into existence. The same holds true for the locking on of a fire-control radar, although the target ship or aircraft would most probably be entitled to consider the situation an imminent attack or hostile intent triggering its right of self-defence (and then an international armed conflict). The latter situation, as well as simulated attacks on foreign warships or military aircraft, shows how difficult it is to clearly distinguish between mere harassment and an imminent use of force/armed attack. However, the existence of an imminent armed attack is relevant for the jus ad bellum only – i.e., for the exercise of the right of self-defence according to Article 51 of the UN Charter. For the determination of the existence of an international armed conflict, there must in fact be a resort to a use of military force; an imminent or allegedly imminent use of force or armed attack does not suffice.
In view of the above findings, the ICRC may consider an amendment or modification of its Commentary on common Article 2, which inter alia holds that an international armed conflict exists “when a situation objectively shows for example that a State is effectively involved in military operations or any other hostile actions against another State, … hampering its military operations”.Footnote 38 Of course, during an armed conflict such conduct will qualify as a contribution to the enemy's military action or a participation in the hostilities. In times of peace, however, the mere hampering of another State's military operations not involving a use of force beyond the threshold of harassment will hardly bring an international armed conflict into existence.
Enforcement measures against foreign warships and military aircraft?
The ICRC Commentary holds that,
under international law applicable at sea, States may, in certain circumstances, lawfully use force against a vessel owned or operated by another State, or registered therein. This may be the case, for example, when coast guards, suspecting a violation of their State's fisheries legislation, attempt to board such a vessel but meet with resistance.Footnote 39
This seems to suggest that, according to the law of the sea, a coastal State may take enforcement measures not only against fishing and merchant vessels but also against foreign State ships, including warships.
However, as far as foreign warships or other State ships enjoying sovereign immunity are concerned, the law of the sea does not provide the coastal State with enforcement rights. The only provision recognizing a coastal State's right to take measures against foreign warships is Article 30 of UNCLOS.Footnote 40 This provision does not explicitly provide a right to use forceful means to compel a foreign warship to leave the territorial sea, although such a vessel would no longer benefit from the right of innocent passage.Footnote 41 In this context it is important to bear in mind that the continuing presence in the territorial sea of a foreign warship which has not complied with a demand to leave may be considered a use of force not only under the jus ad bellum, but also under international humanitarian law.Footnote 42 If the intentional but unconsented-to presence of foreign armed forces in another State's land territory is considered a use of force bringing into existence an international armed conflict, there would be no reason to treat the non-innocent passage of a foreign warship differently, if the coastal State has required it to leave the territorial sea. After all, the territorial sea is part of the territory of the coastal State.Footnote 43 The fact that foreign ships, including warships, enjoy the right of innocent passage would not justify the conclusion that different criteria apply at sea. At first glance, this would not hold true for those parts of the territorial sea forming part of an international strait. Although UNCLOS defines the concept of transit passage,Footnote 44 it is silent on the coastal State's rights with regard to passage that is not expeditious or in normal mode or otherwise contrary to the law of the sea. Seemingly, the coastal State has no right to require the respective ship to leave, or to take enforcement action with a view to terminating transit passage that is not in compliance with the law of the sea. It is, however, important to note that the special rules applying to international straits are without prejudice to the legal status of the sea area, which continues to be territorial sea and, thus, part of the coastal State's territory.Footnote 45 Hence, it could be held that a warship which is engaged in transit passage not in conformity with the law of the sea may be required to leave. If it does not comply, the same rules as those applicable to the territorial sea apply.
If one is not prepared to consider a non-innocent passage of a foreign warship in the territorial sea, including an international strait, a use of force because there is no prohibition of passage that is not in compliance with Articles 19 and 38 of UNCLOS,Footnote 46 then an international armed conflict will only come into existence if the coastal State uses its armed forces to compel the warship to leave the territorial sea or strait.
A use of force against foreign warships or military aircraft in the sea areas and the above airspace beyond the outer limit of the territorial sea will most likely qualify as a use of force and bring an international armed conflict into existence. An illustrative example is the case of USS Pueblo.
USS Pueblo was the second ship in the Auxiliary General Environmental Research (AGER) programme of the United States.Footnote 47 The AGER programme was established in 1965 for the purpose of collecting signals intelligence. AGER operations, which were conducted in coordination with the National Security Agency within the Pacific Command, were also intended to “determine Soviet reaction to a small unarmed naval surveillance ship deployed in Soviet naval operating areas, and to test the effectiveness of this type of ship acting alone”.Footnote 48 The secondary mission of USS Pueblo was “to search for and record any signals emanating from” the DPRK.Footnote 49 Before her deployment, the Pueblo was armed with two 50-calibre machine guns. “Orders to PUEBLO specifically forbade her to approach closer than 13 miles to the North Korean coast.”Footnote 50 On 22 January 1968, a DPRK submarine chaser circled the Pueblo at close range, followed by three DPRK patrol boats. The exact position of the Pueblo at that point in time was, and continues to be, a contested issue between the United States and the DPRK. According to the DPRK government, the Pueblo was 7.1 nautical miles offshore;Footnote 51 according to the US Department of State, she “was seized slightly more than fifteen miles from the nearest land”.Footnote 52 After several warnings by the DPRK warships that remained unheeded, the DPRK vessels opened fire at the Pueblo and eventually she was boarded and taken to Wonsan in the DPRK. One sailor had died; the remaining eighty-two officers and personnel were removed from the ship and taken to Pyongyang, where they were detained until their repatriation on 23 December 1968. According to the DPRK, USS Pueblo “was seized … in the territorial waters of the [DPRK]”, and committed “grave acts of espionage … against the [DPRK] after having intruded into the territorial waters of the [DPRK]”.Footnote 53
Leaving aside the issue of the exact location of USS Pueblo, it is safe to hold that she was not operating within the territorial sea of the DPRK because, in 1968, the 12-nautical-mile breadth of the territorial sea was not yet generally recognized.Footnote 54 Accordingly, the Pueblo’s presence either 7.1 or approximately 15 nautical miles off the DPRK coast can under no circumstances be considered unlawful or a use of force, which would have entitled the DPRK to take enforcement measures. Hence, an international armed conflict only came into existence when the DPRK ships opened fire. Arguably, that international armed conflict lasted until 23 December 1968, the date of the release and repatriation of the crew and personnel.
Use of force against foreign merchant vessels and civil aircraft
In order to trigger an international armed conflict, a use of armed force need not be directed against another State's military forces or military equipment and infrastructure. For the purposes of common Article 2(1), an international armed conflict may also be triggered by a use of force against another State's “territory, its civilian population and/or civilian objects, including (but not limited to) infrastructure”.Footnote 55 However, in the maritime context law enforcement measures involving a use of force taken against foreign merchant vessels will regularly not bring into existence an international armed conflict between the coastal State and the respective flag States, unless the measures extend to the territorial sea of a State other than the coastal State. That said, as stated in the ICRC Commentary, it “cannot be excluded … that the use of force at sea is motivated by something other than a State's authority to enforce a regulatory regime applicable at sea. Depending on the circumstances, such a situation may qualify as an international armed conflict.”Footnote 56 Hence, it is important to clearly distinguish between, on the one hand, maritime law enforcement under the law of the sea, which benefits from a – rebuttable – presumption of legality and which is not considered a resort to a use of force against the flag State or an exercise of belligerent rights; and, on the other, a resort to force at sea outside the law enforcement paradigm.
The law of the sea
UNCLOS and other multilateral and bilateral treatiesFootnote 57 contain provisions entitling States to take enforcement measures against foreign merchant vessels. In view of the limited space available, it suffices to refer to the contribution in this volume by Rob McLaughlin on law enforcement at sea and the peacetime standards for the use of force.Footnote 58 For the purposes of this paper it suffices to mention that the costal State's rights to enforce its domestic civil or criminal law are limited to the internal waters, the territorial sea and, where applicable, the archipelagic waters. Within the contiguous zone, the coastal State may only enforce its customs, fiscal, immigration or sanitary laws.Footnote 59 Within the exclusive economic zone (EEZ), enforcement measures may only be taken within the safety zone around artificial islands, installations and structures,Footnote 60 or in the exercise of the coastal State's sovereign rights enjoyed in the EEZ.Footnote 61 On the high seas, measures against foreign ships may be taken only on the basis of Articles 105, 110 or 111 of UNCLOS.Footnote 62
Accordingly, any action, in particular any use of force, against a foreign vessel will violate the exclusive jurisdiction of the respective flag State, if none of the said provisions provide a legal basis. The same holds true if the force used is disproportionate.Footnote 63 It is, however, open to doubt whether a use of force against a foreign merchant vessel can be considered as bringing an international armed conflict into existence only because there is no legal basis. After all, merchant vessels, while subject to the sovereignty of the flag State, cannot be assimilated to territory (no “swimming territory”). Accordingly, disproportionate or otherwise illegal measures, including disabling fire (i.e., shots into the rudder or bridge) or the sinking of a foreign merchant vessel, cannot be considered a use of force by a State against the flag State.Footnote 64 This may, however, be different if the measures are taken not against individual ships only but against the entire merchant fleet of another State.Footnote 65 Still, it should not be forgotten that, particularly in view of the widespread use of so-called “flags of convenience”, it is virtually impossible to determine that a State has resorted to a use of force against another State's merchant fleet.
Law enforcement or exercise of belligerent rights?
The ICRC Commentary is rather cryptic as regards a “use of force at sea … motivated by something other than a State's authority to enforce a regulatory regime applicable at sea”.Footnote 66 Unfortunately, the respective paragraph provides neither a clarification nor a reference to a situation that could be considered as triggering an international armed conflict by the use of force against foreign merchant vessels. As seen, the lack of a legal basis or the disproportionate nature of the force used will scarcely suffice to qualify as a resort to a use of force against the flag State.
In this context, it may be worthwhile to consider a situation in which a State captures the merchant ships of a single flag State only. At first glance, this may be but yet another example of unlawful conduct rather than an inter-State use of force or a conduct triggering an international armed conflict, in particular if the affected merchant vessels are not sunk. However, under the law of naval warfare, belligerent acts are not limited to attacks. They also include the exercise of so-called prize measures taken against enemy and neutral merchant vessels or civil aircraft.Footnote 67 For the purposes of this paper, prize measures against neutral merchant vessels and civil aircraft can be discarded because maritime neutrality requires the existence of an international armed conflict.
Arguably, an international armed conflict may come into existence by an exercise of prize measures directed against the merchant vessels of only one specific State. By such conduct the State exercising prize measures implicitly qualifies the affected flag State as an enemy and the capture of the flag State's vessels could be considered an exercise of belligerent rights rather than mere maritime law enforcement. In theory, the distinction between an exercise of belligerent rights and maritime law enforcement may be possible. In practice, however, it is rather difficult because the respective measures – visit, search, capture – are more or less identical. Hence, visit, search and capture of the merchant vessels of a single flag State will not as such suffice to justify the conclusion that a State has transited from law enforcement to belligerency; such a conclusion will be possible only if further factors come into play. For instance, the respective State may have established a prize court that is to judge the legality of a capture under the law of naval warfare as distinguished from the peacetime rules of the law of the sea. There may be official government statements, according to which the measures are designed to bring down the flag State's economy. In other words, the determination of whether a State has resorted to an exercise of belligerent rights is dependent upon the circumstances ruling at the time. There is no established or agreed-upon objective criterion that would enable States to clearly distinguish between maritime law enforcement and belligerency at sea.
Use of civilian state agencies for purposes other than law enforcement
The situations referred to above have in common a use of force or aggressive conduct by warships and military aircraft. There are, however, some recent incidents in which States have made use not of their navies or air forces but of their civilian law enforcement agencies, such as their coast guard, which seemingly were not limited to conducting traditional maritime law enforcement operations. In the East and South China Seas in particular, the bordering States have used their coast guard or other vessels to assert their territorial claims to islands, rocks and reefs.Footnote 68 In some instances, the coast guard vessels of two States were engaged in dangerous manoeuvres, including the ramming of ships, and other aggressive operations, including the use of deadly force against foreign fishermen.
The coming into existence of an international armed conflict does not depend upon armed confrontations involving the regular armed forces of two or more States. As rightly stated in the ICRC Commentary, an international armed conflict also comes into existence through armed confrontations involving “non-military State agencies such as paramilitary forces, border guards or coast guards. Any of those could well be engaged in armed violence displaying the same characteristics as that involving State armed forces.”Footnote 69 However, the mere fact that coast guards are used for purposes that may no longer be considered as traditional maritime law enforcement will hardly suffice to justify the conclusion that an international armed conflict has come into existence. After all, the identification of tasks that State organs or agencies are entrusted with is part of the sovereign prerogative that is not limited by international law, including international humanitarian law. In the same vein, there is no rule of international law prohibiting States from asserting territorial claims by resorting to conduct that is perceived of as less aggressive than the deployment of naval forces. For an international armed conflict to come into existence, the conduct of coast guards or other civilian law enforcement agencies must by necessity qualify as a resort to force against another State. Accordingly, the same criteria distinguishing maritime law enforcement and “harassment”, on the one hand, from a resort to force at sea, on the other, apply.
Concluding remarks
The grand battles between navies belong to the past. Direct hostilities between navies, as in the case of the Cheonan, may still occur, but for the time being they will be the exception rather than the rule. Of course, many of the situations and incidents referred to in this paper could have escalated into direct military confrontations between the States involved. The fact that some coastal States have shown, and continue to show, an increasingly aggressive conduct vis-à-vis the vessels of other States is undoubtedly worrying and detrimental to international (maritime) security. This does not concern international humanitarian law, however, as long as the conduct does not qualify as a resort to force by one State against another State. As we have seen, not every confrontation at sea results in an international armed conflict. Although aggressive in nature or legally doubtful, most maritime operations, worrying as they may be, remain within the paradigm of incidents at sea.