Kathleen R. McNamara's study of European Monetary Union and Mark Blyth's analysis of the rise of Reaganomics in the United States. By focusing on how language and rhetoric are used to construct the social reality of the international system, constructivists are often seen as more optimistic about progress in international relations than versions of realism loyal to a purely materialist ontology, but a growing number of constructivists question the "liberal" character of constructivist thought and express greater sympathy for realist pessimism concerning the possibility of emancipation from power politics. Constructivism is often presented as an alternative to the two leading theories of international relations, realism and liberalism, but some maintain that it is not necessarily inconsistent with one or both. Wendt shares some key assumptions with leading realist and neorealist scholars, such as the existence of anarchy and the centrality of states in the international system. However, Wendt renders anarchy in cultural rather than materialist terms; he also offers a sophisticated theoretical defense of the state-as-actor assumption in international relations theory. This is a contentious issue within segments of the IR community as some constructivists challenge Wendt on some of these assumptions (see, for example, exchanges in Review of International Studies, vol. 30, 2004). It has been argued that progress in IR theory will be achieved when Realism and Constructivism can be aligned or even synthesized. An early example of such synthesis was Jennifer Sterling-Folker's analysis of the United States’ international monetary policy following the Bretton Woods system. Sterling-Folker argued that the U.S. shift towards unilateralism is partially accounted for by realism's emphasis of an anarchic system, but constructivism helps to account for important factors from the domestic or second level of analysis. Recent developments A significant group of scholars who study processes of social construction self-consciously eschew the label "constructivist". They argue that "mainstream" constructivism has abandoned many of the most important insights from linguistic turn and social-constructionist theory in the pursuit of respectability as a "scientific" approach to international relations. Even some putatively "mainstream" constructivists, such as Jeffrey Checkel, have expressed concern that constructivists have gone too far in their efforts to build bridges with non-constructivist schools of thought. A growing number of constructivists contend that current theories pay inadequate attention to the role of habitual and unreflective behavior in world politics, the centrality of relations and processes in constructing world politics, or both. Advocates of the "practice