In this article we bring together opposing international relations theories to better understand U+S+ foreign policy, in particular foreign trade and aid+ Using votes in the U+S+ House of Representatives from 1979-2004, we explore different theoretical predictions about preferences for foreign economic policy+ We assess the impact of domestic factors, namely political economy and ideological preferences, versus foreign policy pressures+ Our three main results highlight the differential effect of these factors in the two issue areas+ First, aid preferences are as affected by domestic political economy factors as are trade preferences+ Second, trade preferences, but not economic aid ones, are shaped by the president's foreign policy concerns; for economic aid, domestic political economy factors matter more than foreign policy ones+ Third, aid preferences are shaped more by ideological factors than are trade ones, but ideology plays a different substantive role in each+ Different constituencies support aid and trade+ This finding has implications for foreign policy substitutability, "the internationalist coalition" in U+S+ foreign policy, "statist" theories of foreign policy, and the connection between public opinion and legislative voting+ International Organization 65, Winter 2011, pp+ 37-68