Maybe relevant: "The results of cross-sectional and time-lagged analyses suggest that U.S. foreign policy is most heavily and consistently influenced by internationally oriented business leaders, followed by experts (who, however, may themselves be influenced by business). Labor appears to have significant but smaller impacts. The general public seems to have considerably less effect, except under particular conditions."

Who Influences U.S. Foreign Policy? LAWRENCE R. JACOBS and BENJAMIN I. http://journals.cambridge.org/action/displayAbstract?fromPag...