This paper analyses the development of the US approach to the ASEAN Regional Forum (ARF), from 1991 onwards. It examines theories of why a superpower would participate in a multilateral security institution, and investigates the motivations for the attitudes and extent of participation of the George H. Bush, Clinton and George W. Bush administrations towards the ARF. It argues that, in the post-Cold War period and in the face of a rising China, US East Asia strategy has been geared towards retaining the American preponderance of power. Thus, the US has pursued a strategy of containment and deterrence centred upon the regional bilateral alliance structure. Multilateral institutions have been treated as a supplementary means of supporting the secondary strategy of engaging with China. However, the ARF is not viewed as one of the important institutions through which to fulfil this supplementary aim. Because it cannot deal with the key regional security issues, the ARF is seen as a low-stakes arena by Washington. But the paper concludes that US participation in the ARF may nevertheless be crucial in boosting the legitimacy of American security interests in the region, thus helping to safeguard US preponderance.