The “two-good theory” is a theory of foreign policy that is meant to apply to all states in all situations; that is, it is general. The theory is simple and assumes that states pursue two things in theory with respect to foreign policies: change (altering aspects of the status quo that they do not like) and maintenance (protecting aspects of the status quo that they do like). It also assumes that states have finite resources. In making these assumptions, the theory focuses on the trade-offs that states face in constructing their most desired foreign policy portfolios. Further, the theory assumes that protecting realized outcomes is easier than bringing about desired changes in the status quo.
The theory assumes that states pursue two goods instead of the more traditional one good; for realism, that good is “power,” and for neorealism, it is “security.” This small step in theoretical development is very fruitful and leads to more interesting hypotheses, many of which enjoy empirical support. The theory captures more of the dynamics of international relations and of foreign policy choices than more traditional approaches do.
A number of empirical tests of the implications of the two-good theory have been conducted and support the theory. As the theory can speak to a variety of foreign policy behaviors, these tests appropriately cover a wide range of activities, including conflict initiation and foreign aid allocation. The theory enjoys support from the results of these tests.
If the research relaxes some of the parameters of the theory, the investigator can derive a series of corollaries to it. For example, the initial variant of the theory keeps a number of parameters constant to determine the effect of changes in capability. If, however, the investigator allows preferences to vary in a systematic and justifiable manner (consistent with the theory but not established by the theory), she can see how leaders in a range of situations can be expected to behave. The research strategy proposed, in other words, is to utilize the general nature of the two-good theory to investigate a number of interesting and surprising implications. For example, what may one expect to see if the United States supplies a recipient state with military aid to counter a rebellion? Under reasonable circumstances, the two-good theory can predict that the recipient would increase its change-seeking behavior by, for instance, engaging in negotiations to lower trade barriers.
Why America's Grand Strategy Has Not Changed: Power, Habit, and the U.S. Foreign Policy Establishment