In the aftermath of the Cold War, international relations between Cold War allies became more difficult. Leaders of previously allied nations were required to conduct tactful economic negotiations in order not to arouse tensions that had previously been overlooked. The situation described above conforms most closely to which one of the following propositions? ['International economic competition is a greater cause of tension than is international military competition.', 'Bonds between allies are stronger when they derive from fear of a common enemy than when they derive from common economic goals.', 'Economic matters are considered unimportant during periods of actual or threatened war.', 'A common enemy contributes to a strengthened bond between nations, enabling them to ignore economic tensions that would otherwise be problematic.']