Domestic politics is central to whether, how and when revolutionary states become socialized. Although socialization is supposed to operate most heavily on new actors, in fact revolutionary states often resist such processes, especially because they are hard to reassure. Domestic and international factors are likely to interact, as they did with Gorbachev's USSR and probably are doing with contemporary Iran, and this points to the importance of domestic politics within the other states in the system as well. For the United States domestic politics enters in both directly and in the American perceptions of the other's domestic system because of its tradition of 'second image' thinking, to use Waltz's term.