Bilateral relations between U.S. and Russia will be more important to Arctic security than U.S. non-party status to UNCLOS
If the U.S. Senate ratifies the Convention on the Law of the Sea of 1982, Russia will not witness any significant changes in bilateral relations in the Arctic. It is obvious that the U.S. intends to apply the Convention only when it coincides with its national interests. Potential conflicts will be resolved through bilateral negotiations rather than UNCLOS provisions directly.
Since the Convention does not oblige all contentious issues to be decided within its rules and institutions, the United States can either appeal to precedent or refuse to discuss an inconvenient problem in terms of the Convention. Apparently, some Russian experts underestimate the fact that under international law, common law prevails over codified law. This allows the U.S. to bypass the Convention and is all the more reason to not consider it a universal source of law on Arctic issues.
In line with this logic, experts from the Ministry of Defense and the Department of State submitted their official conclusions to the U.S. Senate in which they found that ratification would not impose any restrictions on the military.
Moreover if the Convention was ratified, the U.S. could appeal to the right of transit in territorial waters enshrined in the Convention as grounds for legal military presence not only in the Barents Sea, but also anywhere in the world. In case of complaints about the inadmissibility of covert presence or military activities in territorial waters, the United States could exercise the right of self-interpretation, challenging what is meant by military activities in the particular case (Article 298-1 of the Convention).
U.S. military activities cannot be a matter of contention within the framework of the Convention. Similarly, Russia will not receive any positive changes to the delimitation of the Bering Sea or defining the boundary line in the Chukchi Sea and beyond the exclusive economic zone towards the pole.
Thus, strategic environment and level of cooperation between Russia and the United States in the Arctic will be based on the state of their bilateral relations in general, and not on the U.S. decision of whether or not to ratify the UN Law of the Sea.