Abstract: Recent empirical work (Alesina and Rosenthal 1995; Erikson 1990) has shown that economic conditions may not have influenced House midterm elections since 1915. I argue that economic conditions may have influenced House midterms in the late 19th and early 20th centuries, when Congress dominated economic policy-making, parties offered starker positions on economic issues, and national issues dominated House elections. As the 20th century progressed, congressional power over the economy declined, the parties converged over certain economic policies, and district-level forces grew more important in elections. I test the stability of the relationship between the economy and House midterms over time, using F-tests to show how the impact of macroeconomic conditions has changed in House midterm elections from 1872 to 1994. The results indicate that the gross national product (GNP) influenced House races before 1913 but, as the 20th century continued, the importance of the economy on House midterms declined.