Teachers unions are undoubtedly a potent force in American education and politics. But questions about what teachers unions do, and why, are so politicized that the answers you get typically say more about who you ask than about teachers unions themselves.On this episode of The Report Card, Nat Malkus speaks with Michael Hartney, whose new book, "How Policies Make Interest Groups: Governments, Unions, and American Education," explores these questions and others. Nat and Michael discuss how teachers unions impact students, affect education policy, and became the political powerhouses they are today.Michael Hartney is an assistant professor of political science at Boston College, a Hoover Fellow at Stanford University’s Hoover Institution, and an adjunct fellow at the Manhattan Institute.  Show Notes:How Policies Make Interest Groups: Governments, Unions, and American EducationTeachers’ Unions and School Board Elections: A ReassessmentRevitalizing Local Democracy: The Case for On-Cycle Local ElectionsTeachers Unions in the Post-Janus World