Why do major powers attempt foreign-imposed regime change (FIRC)? This article builds on existing security theory, proposing that a major power looks for signals that a government might exit that major power’s international hierarchy and/or enter an adversary’s hierarchy. Major powers are more likely to attempt FIRC against states that signal shifting preferences. The article tests the theory on American FIRC attempts from 1947 to 1989, covert and overt, failed and successful, proposing that when a hierarchy member or neutral state engaged in economic expropriation, this signaled possible exit from the US hierarchy and/or entry into the Soviet hierarchy, making a US FIRC attempt against that state more likely. It also presents an alternative theory, that economic special interests drove US FIRC attempts. Using new data on expropriations, the article supports the security theory, as expropriations by US hierarchy members made FIRC attempts more likely, but does not support the special interests theory.