U.S. Department of Defense has repeatedly affirmed value of freedom of navigation program

More than a decade after the adoption of UNCLOS, the Department of Defense issued an Ocean policy review paper on “the currency and adequacy of U.S. oceans policy, from the strategic standpoint, to support the national defense strategy,” which concluded that U.S. national security interests in the oceans have been protected even though the U.S. is not party to UNCLOS:

U.S. security interests in the oceans have been adequately protected to date by current U.S. ocean policy and implementing strategy. U.S. reliance on arguments that customary international law, as articulated in the non-deep seabed mining provisions of the 1982 law of the Sea Convention, and as supplemented by diplomatic pro- tests and assertion of rights under the Freedom of Navigation program, have served so far to preserve fundamental freedoms of navigation and overflight with acceptable risk, cost and effort.²²

This is not to say that the Department of Defense does not support U.S. accession to UNCLOS—it certainly does. However, the Department of Defense does not, and cannot, say that U.S. membership in UNCLOS is absolutely essential to the preservation of navigational rights or that the United States is incapable of protecting those rights unless it accedes to the convention.

The U.S. Navy thrived for more than 180 years from its birth in 1775 through two world wars and developed into a global maritime power, all without membership in UNCLOS. in 1958, the principles of high seas freedom and innocent passage through territorial waters were codified in the first round of law-of-the-sea conventions. Between 1958 and 1982, the Navy continued to fulfill its mission on a global scale. UNCLOS was adopted in 1982, duplicat- ing the navigational provisions of the 1958 conven- tions and “crystallizing” the concepts of transit pas- sage and archipelagic sea-lanes passage. Since 1982 through the end of the Cold War and to the present day, the Navy continues to prosecute its mission as the world’s preeminent naval power.