ABSTRACT
U.S. leadership has been a key pillar of the nuclear nonproliferation regime since its founding. Domestic role commensurability between Congress and the executive branch, as well as an international role allocation between nuclear and non-nuclear weapons states, has long contributed to the stability of the U.S. leadership role. The Iran nuclear crisis severely contested America’s leadership role. Domestic role commensurability had initially driven the U.S. role away from its allies’ role expectations. However, under the Obama administration, U.S. leadership became slowly but steadily more alter-oriented, while domestic polarization increasingly contested this role change. This inclined the Obama administration to seek a domestic role change in order to stabilize its international leadership role as a response to the crisis.
