In 1978, Argentina and Chile were poised at the brink of war over disputed possession of the Beagle Channel islands located near the southern tip of South America. Despite provocative military maneuvering and inflammatory rhetoric from both sides, Argentina's ruling military junta pulled back just short of attacking the territory occupied by Chile, and eventually both sides reached a peaceful settlement. Only four years later, Argentina launched a surprise invasion of the British-held Falkland Islands in the South Atlantic. Why did Argentina choose to go to war with Britain in 1982 but not with Chile in 1978? What factors led to a grab for the Falklands instead of the Beagle Channel islands? Prospect theory, borrowed from cognitive psychology, may hold the answer. This theory proposes that decision-makers tend to be more risk-averse when they are facing a potential gain and more willing to take risks when they are confronting a potential loss. Therefore, the junta refrained from invading the Beagle Channel islands because they were more secure in their political position and therefore facing a potential gain, but chose to invade the Falklands because they were insecure in their position and facing the loss of political power.