The United States sells Taiwan weapons. This has been true since the Taiwan Relations Act of 1979 mandated that the US provide Taiwan with arms of a defensive character sufficient to maintain its self-defense capability. The commitment has been honored through administrations of both parties, at varying levels of political visibility and diplomatic cost. It has also produced a backlog of undelivered weapons that, as of the mid-2020s, runs to billions of dollars in contracted but unshipped equipment — a gap between what Taiwan has bought and what it has received that raises serious questions about the operational meaning of the commitment.