Stimulated by social scientists' and especially social psychologists' contributions during World War II, as well as by America's post-war economic and population growth, the period from 1945 to 1970 was widely viewed as a "Golden Age" for American social science. Interdisciplinary social psychology arguably was in the vanguard of these developments. Progress since then have been variable and in some ways negative for social psychology, not only as an interdisciplinary field, but also within its parent disciplines of psychology and especially sociology, where social psychology could plausibly become extinct within twenty-five years. The decline of social psychology as a field and a broad influence on the social sciences, society, and public policy has coincided with a rise of economics to an analogous vanguard position. Understanding the reasons for and implications of these trends has been limited, with a focus on analyses of developments within particular disciplines. However, developments across the social sciences, and society more broadly, are equally or more important to understanding these trends. Future prospects also depend heavily on these broader societal forces, but the inertial tendencies of trajectories since 1970 within and between social science disciplines and fields will necessarily play a major role. The twenty-first century offers the prospect of renewed importance of social psychology in a more interdisciplinary and integrated set of social and policy sciences, if social psychologists and the parent disciplines of sociology and psychology are prepared to capitalize on and take leadership of emerging opportunities. (Contains 3 figures, 2 tables and 1 footnote.)