Prosocial behavior is common in international politics, but states’ reaction to help has received scant attention. When a state’s territory is invaded and occupied by another state, it is common for third countries to intervene to liberate the first state’s territory. States intervene in other states to impose or defend regimes. In fact, these behaviors result in a key feature of the contemporary international system: the system eliminates domestic political regimes much more than it eliminates states. Also, some states give aid that amounts to a significant part of the recipient’s gross national product. If these forms of help succeed in dealing with the problem better than the recipients could have by themselves, then one would expect that the recipient state?s leaders, and perhaps the public too, would be pleased and grateful. But sometimes, they are not. Iraqis’ discontent has surprised their U.S. liberators and occupiers. Negative reaction to help may have disrupted alliances between major powers, as between China and the Soviet Union, or between France and the United States. I explain negative reaction to help with two social psychological conditions. First, according to attribution theory, people want to understand why they need help. If state agents can attribute their state?s need to external forces, then they will be able to maintain positive self-esteem. If not, their attribution of the need to an internally caused failure would threaten their self-esteem. Second, according to social exchange theory, unreciprocated giving signals material hierarchy between the donor and the recipient, and naturalizes it into a moral hierarchy of generosity and gratitude. These two costs should be highest for major powers. Moreover, major powers have the greatest freedom from material constraints to assert their independence from the donor through negative reciprocity. I integrate these two mechanisms in terms of the sociometer theory of self-esteem, in which people care about their self-esteem not for its own sake, but because it is a subjective monitor of their eligibility for lasting, desirable relationships, including membership in desirable groups. Another psychological theory, called reactance theory, and structural realism explain reaction to help similarly, and provide an alternative hypothesis. According to reactance theory, people value their freedom for its own sake, and any perceived reduction in freedom results in the unpleasant psychological state of reactance, which motivates them to restore the lost freedom. According to structural realism, states value freedom of choice because they are uncertain about other states’ future intentions. If the recipient state’s leaders perceive that the donor’s conditions for help restricts their freedom, then they are likely to respond with negative reciprocity, if the distribution of material capabilities allows them to do so. I test my explanation and the alternative for their ability to explain the variation in policies of major powers toward states that have liberated them from foreign occupation, imposed or defended their regimes, or given them significant economic aid. In this way, I can help explain another undertheorized issue: the prestige motive in international relations. [ABSTRACT FROM AUTHOR]