He is best known for his work completely reinventing "geopolitics" as a field of study and for his theoretical and empirical efforts at showing how national politics is best understood in terms of the geographical dynamics of "places" and how they are made out of both local and long-distance determinants.

John Agnew was President of the Association of American Geographers, the main professional organization for academic geography in the United States, from 2008 to 2009.

Perhaps his most polished arguments in this area are in Hegemony: The New Shape of Global Power, which won a Choice Award as an Outstanding Academic Title for 2005, and in “Sovereignty Regimes”, a long article that appeared the same year and has been transformed into a book length project, Globalization and Sovereignty (2009) which also won a Choice Outstanding Academic Title Award.

This work has attracted the attention of international relations scholars interested in paying more attention to the ways in which “geography” enters into the theory and practices of “international relations.” Agnew's recent work in this area, specifically on the European origins of the modern state and what this signifies for contemporary statehood in southeastern Europe, was helped by the award of a John Simon Guggenheim Foundation Fellowship for the academic year 2003–2004.

Claiming that the surge merely sealed the fate of Sunni and mixed Sunni/Shia neighborhoods already reduced in population by previous violence, this research received an enormous amount of coverage in the press and the blogosphere, not least from right-wing bloggers in the US defending the Bush-McCain claim that the surge "had worked" but without any sort of empirical information to justify their politically inspired arguments (S. Tavernise and A.W.

Lehren, "A grim portrait of civilian deaths in Iraq" New York Times, 22 October 2010) During early 2009, a team led by Thomas Gillespie and Agnew of UCLA used satellite-aided geographical analysis to pinpoint three compounds in Parachinar [Pakistan] as likely hideouts of the Al-Qaeda leader Osama Bin Laden in 2001.

Much of this, however, failed to note the ironic tone of the MIT International Review paper (2009), "Finding Bin Laden", reporting the research with its emphasis on why so little effort seemingly had been put into finding the al-Qaeda leader after 2001 and the stake of US governments in keeping the myth of Islamic terrorism going as a basis for an endless new war recapitulating the "success" of the Cold War in mobilizing US identity and formulating a US foreign policy to which others could be recruited.