This book challenges the conventional wisdom that unified party control of the US government leads to more effective governance. David R. Mayhew, a distinguished political scientist, examines the period from 1946 to 1990, a time marked by increasing instances of divided government where the presidency and Congress are controlled by different parties. Despite the common assumption that such divisions hinder legislative productivity and oversight, Mayhew's analysis of lawmaking and investigations suggests that unified party control has made little discernible difference in the government's overall effectiveness.

The book's central argument, that divided government does not significantly impede governmental effectiveness, offers a counterpoint to prevailing assumptions in political science. Mayhew's rigorous empirical approach, focusing on concrete measures of lawmaking and investigations, provides a data-driven foundation for his conclusions. The work is likely to be of interest to scholars and students of American politics, legislative behavior, and comparative government. Its findings suggest a need to re-evaluate the perceived benefits of party unity in the US federal system.