The Treaty on the Prohibition of Nuclear Weapons (TPNW), colloquially known as the “Ban Treaty,” is hailed by supporters as the beginning of the end for nuclear weapons. Nuclear weapons states, including the United States, have criticized the treaty on its shortcomings as a legal instrument for disarmament. Beyond this criticism, the United States has done little to engage with the Ban Treaty or its supporters. But ignoring the Ban Treaty is a bad idea that will exacerbate the divide between nuclear and non-nuclear states and could lead to a dangerously uneven pace of international disarmament.