As the greatest military power in the Asia-Pacific, the U.S. depends on the cooperation of its allies. In the past, Washington has had to recognize that support is not always forthcoming. Using the example of relations between the U.S. and Thailand, this article tries to establish how the reliability of an ally can be assessed. For this purpose, the options of military access for American forces are first analyzed. Subsequently, the actions of the kingdom are explained from a theoretical point of view: Is Bangkok following a policy of bandwagoning vis-à-vis Washington? Finally, against this background, the possible behaviour of Thailand during a crisis in the Taiwan Strait is discussed: How reliable will the American ally be when it counts?