Michael Leifer’s passing over a decade ago has done little to diminish the force of his scholarly ideas and their continued relevance to the study of regional order and security of contemporary Southeast Asia. Leifer’s intellectual influence is apparent in the way analysts of different theoretical persuasions continue to grapple with and debate over the problem of regional order in Southeast Asia. In so doing, they rely on terms of reference originally defined by Leifer. This article reviews and assesses a number of noteworthy insights from Leifer’s oeuvre against the contemporary political-strategic situation of Southeast Asia and its immediate extra-regional context. The insights include the elusiveness of regional order, the primacy of the balance of power, and the emphasis on conservation rather than innovation in the management of regional security in Southeast Asia. While Leifer’s ideas are by no means timeless, they continue nonetheless to speak in telling ways to the security challenges facing Southeast Asia today.