Presidential Coattails in Historical Perspective

Two methods are used to measure presidential coattails in House elections in various electoral periods since 1868. In the direct model, House votes are determined directly by presidential votes plus extraneous and local effects. This allows separate measurements of the seats-votes relationship (swing ratio) and of the behavioral connection between presidential and congressional voting. In the simultaneous determination model, votes for both offices are simultaneous results of national issues, while factors specific to the presidential campaign enter presidential voting directly and congressional voting indirectly. The two models corroborate one another and are consistent with previous studies. An increase in coattail voting during the New Deal period is found to be due to an increase in the swing ratio over the levels of previous years, while the behavioral connection remained almost constant. On the other hand, a historically low coattail effect in recent years has been due to a reduction in the behavioral connection below any previous levels, while the swing ratio (viewed over a period of 15 years) is about what it was early in this century. Implications for executive-legislative coordination are discussed.