It is well understood that trust in government responds to the performance of the president, Congress, and the economy. Despite improved government performance, however, trust has never returned to the levels witnessed in the 1950s and 1960s. Social capital may be the force that has kept trust low. If so, we need to assess the relative contributions of both government performance and social capital at the macro level. Using macrolevel data, the analysis, here, is designed to capture the variation over time in both social capital and government performance and let them compete to explain the macro variation in trust. The empirical results demonstrate that both government performance and social capital matter, but that social capital appears to be the force which accounts for the decline in trust over the last 40 years.