American Government: Power and Purpose uses a unique Five Principles of Politics framework to helps students make sense of American politics. This rigorous, analytical approach, supported by research, scholarship, and data, has been developed by an author team of top scholars, including newest coauthor Hahrie Han (Johns Hopkins), who brings her research on how groups come together to impact American government to the collective action principle. Veteran author Steven Ansolabehere (Harvard), offers a comprehensive discussion of the 2026 midterm elections and results using the rationality principle. The book’s courseware, including an interactive Norton Illumine Ebook and adaptive InQuizitive learning tool, helps students gain confidence with key course concepts and practice applying the Five Principles framework to American politics.

Highlights of this edition’s new content:

• Four new Analyzing the Evidence features from the next generation of top scholars introduce students to contemporary research and help them explore how data can provide answers to big questions about American government. Each infographic is accompanied by a dynamic data figure and Check Your Understanding questions in the Norton Illumine Ebook, making these features interactive and assignable.
• New coverage of the Institution principle by Ken Shepsle brings the impact of the Trump administration’s second term into focus. In Chapter 9, the author breaks down President Trump’s enduring impact on the courts, as well as the results of important hearings on some of his executive actions. In Chapter 6, the author explores the implication of Republican control, and how it shaped the policy agenda.
• New coverage of the collective action principle by Hahrie Han—which offers a lens for exploring how people come together to enact change—looks at the movements that have supported and fought against the Trump administration's actions. Chapter 8 looks at how the bureaucracy has been impacted by the changes led by the new Department of Government Efficiency, originally led by Elon Musk, and what these reductions mean for the government.
• New coverage of the rationality principle by Steven Ansolabehere analyzes the 2026 midterm elections, looking at the Congressional races, campaigns, elections, and results. By applying the rationality principle, Ansolabehere helps students make sense of the actions taken by the politicians and the voters at the polls. A fully revised Elections chapter, complete with updated data, examines the issues that moved the needle in 2026, and explores what these trends might mean looking forward to the 2028 presidential election.
• Two New Timeplots figures use data to illustrate trends over time and help students use data to make sense of American politics.