The expropriation of U.S. companies —such as the International Petroleum Company— has been signaled in historiography as a decisive factor in determining the stance of the U.S. government towards Peru’s military regime. This study shows that Congressional motivations were rather of a political nature, associated with the seizure of U.S. fishing vessels within the 200 nautical miles of territorial waters claimed by Peru. Moreover, the policies implemented by Peru’s military government were used by a group of congressmen to advance their own agendas, criticizing U.S. foreign policy at a moment of conflict of powers between the Executive and the Congress.