jats:titleABSTRACT</jats:title>jats:pThis article tracks the shifting contours of John Maynard Keynes's invocation of certain ideas associated with Thomas Robert Malthus, between 1914 and 1937 especially. These ‘Malthusian moments’ in Keynes's work form a triptych. In pre-war thinking about global population dynamics as a Malthusian ‘devil’ threatening national political and economic stability, Keynes found optimism in the thought that modern political economy could be repurposed to avoid the horns of such a dilemma. In the 1920s, he moved to consider the international, and particularly European, responses to both population and to the developing Malthusian ‘devil’ of unemployment. Finally, in the 1930s, Keynes's view became increasingly domestic, focusing on ways that these devilish twin problems could be managed by nation-states organized for prosperity and self-sufficiency. Across these moments, Keynes sought to assert the power of past political and economic ideas to aid in the formulation of present policy, by continuously (if rather loosely) invoking the Malthusian trope of ‘effective demand’.</jats:p>