The AP US Government course utilizes a condensed and edited version of these two textbooks. The original texts are located at Libretext and/or Pressbook.
Hubert, D. Attenuated Democracy. (2021). Salt Lake Community College. Attenuated Democracy helps students understand who has power in the United States political system, why they have power, and what ordinary people can do to better balance the system.
Lumen. American Government. (2021). Lumen Learning. American Government provides a strong understanding of the United States government, civic engagement, and the entities and processes that shape U.S. democracy.