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.

Taiwan’s air force operates approximately 400 combat aircraft, including upgraded F-16A/Bs, the domestically developed Indigenous Defense Fighter, and a dwindling number of older French Mirage 2000s. Against it stands the People’s Liberation Army Air Force, which fields approximately 2,000 combat aircraft including fifth-generation J-20 stealth fighters, advanced Su-35s acquired from Russia, and large numbers of fourth-generation J-10 and J-16 multirole fighters that outperform Taiwan’s F-16s in some performance parameters. The numerical imbalance is significant. The qualitative gap, when the J-20 enters the calculation, is severe. Taiwan’s air force cannot achieve air superiority over the strait in a sustained conventional air campaign against the PLAAF.