Rising maritime powers across the globe are reinterpreting customary international law to promote their own national interests -- including in ways that may conflict with longstanding maritime norms and American interests. Nowhere is this more apparent than in the South China Sea, where China's outsized claim to the entire region flies in the face of both traditional practices and LOSC. But China is not the only offender. Burma, Thailand, and others are joining China in more restrictive interpretations of maritime navigational rights, including anti-access norms that could constrain the U.S. Navy's ease of access in this crucial maritime domain.

Unfortunately, the United States is not in a position to rebuff these restrictive interpretations and protect the maritime norms that have been so beneficial to the global economy and U.S. security. U.S. failure to ratify the treaty has prevented the United States from taking a seat at the table to avail itself of the convention's established legal frameworks, such as the Law of the Sea Tribunal. And while the United States sits on the sidelines, other countries are engaging in discussions of maritime law, and in some places working toward consensus on issues that could have consequences for the United States for decades. Joining the treaty will allow the United States to lead these important discussions and, more importantly, enable the United States to negotiate with countries from a position of strength to protect the customary practices codified by the convention.

Ratifying LOSC will also strengthen a range of ongoing U.S. security activities. The U.S. Navy and U.S. Coast Guard are our key instruments of power at sea and ratifying LOSC will strengthen their ability to do their job and work with others to protect U.S. interests, including areas such as counter proliferation and counter piracy. More importantly, ratifying the convention would give the U.S. Navy and Coast Guard the strongest legal footing for their actions, including in places like the Strait of Hormuz, where Iran has threatened to close access to the international passageway in direct violation of the convention. As Chairman of the Joint Chiefs of Staff General Martin Dempsey recently said, "It validates the operations we conduct today and realizes our vision for a secure future."

The navigation and overflight freedoms we require through customary international law are better served by being a party to the Convention that codifies those freedoms. Being a party to the Convention is even more important because the trend among some coastal states is toward limiting historical navigational and overflight freedoms. Would-be adversaries, or nations that do not support the particular missions or activities we undertake, will be less likely to dispute our lawful use of the sea and air lanes if we are parties to the Convention. We support the Convention because it protects military mobility by codifying favorable transit rights in key international straits, archipelagic waters, and waters adjacent to coastal states where our forces must be able to operate freely.