John Tirman, an MIT scholar in political theory and expert on U.S.-Iran relations and human security, passed away on the morning of Aug. 19 after suffering cardiac arrest. He was 72. Since 2004, Tirman served as the executive director of and principal research scientist at the MIT Center for International Studies (CIS). During this time, he was a prolific and thoughtful — but always modest — leader of many of the center’s initiatives. He spearheaded several projects on U.S.-Iran relations, and convened conferences and published on the regional dimension of the Iraq…