It is not a credible position for the US to rely on customary international law precedents from half a century ago

And this expression of the national interest has been the precise locus of the isolationist backlash against UNCLOS. Treaty opponents have been unable to mount a serious challenge to the underlying substantive policy goals in favor of ratification of the Convention by the United States. The ability of the U.S. Navy to project power, under its Freedom of Navigation (FON) program as part of UNCLOS,⁹ has received a lot of negative attention of late, as coastal states (especially archipelagic nations and those bordering strategic straits)¹⁰ have renewed attempts to limit access by constraining the doctrines of innocent and transit passage under UNCLOS. Treaty opponents have cleverly argued that there is no need for the U.S. to ratify UNCLOS because all of its FON provisions are already reflected in customary international law (CIL). The problem – as recognized by the Pentagon – is that CIL formulations for FON are largely derived from the state practice following the 1958 Geneva Conventions (to which the U.S. is a party).¹¹ It is not a credible international legal position, however, to rely on CIL frozen-in-time nearly a half-century ago. In order for the U.S. to effectively object to improper impositions of navigation interferences by coastal states, there must be a baseline (both literally and figuratively)¹² of state behavior – and that standard is UNCLOS.