American political theorist, professor of literature at Duke, and for a quarter-century the longtime collaborator of the Italian Marxist Antonio Negri. The Hardt–Negri partnership produced one of the most-discussed works of political theory of the early 21st century: Empire (2000), a book that argued the old model of imperialism — competing national powers projecting force outward — had been superseded by a decentered, networked global sovereignty (Empire, capitalized) with no outside and no center, to which the appropriate democratic response was the self-organization of the multitude. The argument drew heavily on Negri's reading of Marx (especially the Grundrisse) and on Italian autonomist theory; Hardt brought philosophical training in Deleuze and an American academic platform.
Multitude (2004) and Commonwealth (2009) completed the trilogy, elaborating the democratic-alternative side of the argument. Assembly (2017) and Declaration (2012) responded to the post-2011 wave of global movements (Occupy, Tahrir, the Indignados) that the Hardt–Negri framework had seemed to predict. Academic reception has cooled — many of the specific claims about post-imperial sovereignty look dated after 2014 and 2022 — but the vocabulary (Empire, multitude, immaterial labor) remains in circulation, and the ambition of attempting a positive democratic theory from within Marxism marks the trilogy as an unusual intellectual event.