On Sunday November 25th, three Ukrainian vessels were captured by the Russian coast guard while travelling through the Kerch Strait and several soldiers were injured in the short firefight which ensued. The strait, which lies between the Russian mainland and the disputed territory of Crimea has been a flashpoint for conflict between the two nations already, with the Kremlin notably building a bridge over the strait in a symbolic display of Russian control of the region.
Both countries have argued that the other country violated international law. Russian officials claim that the Ukrainian vessels violated their territorial waters, while Ukrainian authorities have pointed to the UN Convention on the Law of the Sea as evidence that, in fact, it is Russia who has violated international law.
The question of who violated international law ultimately comes down largely to the legal standing of Crimea. The 2014 annexation of Crimea precipitated by a revolution in Ukraine is not recognized by Ukraine, the U.S. or the vast majority of nations. However, some nations including China, North Korea and Iran have recognized it. Russia, operating under the understanding that Crimea is a Russian holding, has claimed that the vessels were in Russian “territorial sea,” which extends up to 12 nautical miles from a country’s coastline.
Looking to the 2014 referendum on the legal status of Crimea, it becomes clear that both internal and international law were not sufficiently upheld. Article 2 of the Ukrainian Constitution establishes that “Ukraine shall be a unitary state” and that the “territory of Ukraine within its present border is indivisible and inviolable.” Article 134 goes further than this, calling Crimea an “inseparable constituent part of Ukraine.” However, these articles are not enough to gauge the legality of the referendum in terms of international law, as Constitutional violations represent domestic, rather than international, matters. According to the Venice Commission’s Code of Good Practice referendums can only be held on one question, which should be answerable with a yes or a no. Further, there must be a regulatory referendum law, a neutrality of public authorities, and an absence or restraint of military forces of either side of the referendum. None of these conditions were sufficiently met by the referendum, rendering it invalid by international law. Given the unchanged legal status of Crimea with respect to international law, there is a customary claim to coastal State status which can be made by Ukraine.
It seems that, even if the Russian premise that it controls Crimea is accepted, Russian actions clearly violated customary international law and agreements in multiple ways. Principally, a 2003 bilateral agreement between Russia and the Ukraine guarantees free navigation in the sea of Azov and the strait of Kerch by state non-commercial vessels. This agreement also notes that dispute settlement must be regulated by agreement between the parties, which means that, absent a consensus on the legality of this action by Russia and Ukraine, the issue of legality must default to precedent. Russia has repeatedly violated this agreement. In July 2017, the Russian Ministry of Transport implemented an order which allows Russian authorities to deny any vessel except Russian warships access to the Sea of Azov during specified time periods.
Finally, the 1997 Treaty on Friendship, Cooperation and Partnership between Ukraine and the Russian Federation (FCN-Treaty) states that Russia and Ukraine guarantee freedom of transit across each other’s territory in accord with generally recognized norms of international law. This treaty calls to mind a central question: does customary international law support the Ukrainian or the Russian side of this dispute? If the waters are determined to be internal waters, the ICJ’s 1992 judgment in the Land, Island and Maritime Frontier Dispute can be referenced, as there was an “existing right of innocent passage” both because of “historical reasons” and “practical necessities.” The existence of multiple written agreements supporting free navigation further suggests preexisting customary freedom of transit for Russian and Ukrainian ships. The previous discussion of the legal status of Crimea makes it abundantly clear that, in the final analysis, Ukraine has the most clear and rigorous claim to customary coastal State rights in the area in which the Ukrainian ships were seized.