Matt Grossmann and David A. Hopkins are the authors of Asymmetric Politics: Ideological Republicans and Group Interest Democrats (Oxford University Press, 2016). Grossmann is director of the Institute for Public Policy and Social research and associate professor of political science at Michigan State University; Hopkins is assistant professor of political science at Boston College. With heated confirmation hearings occurring on Capitol Hill and the inauguration days away, Republicans and Democrats are debating what makes a good Cabinet official and what makes good federal policy. Why is it that the two parties have such different visions for what makes good policy and the importance of ideology? Asymmetric Politics offers an answer: the GOP has been, at its core, an ideological movement while the Democrats are a coalition of social groups. Hopkins and Grossmann support this argument with a huge amount of information about the electorate, party organizing, and elected officials. They show that the polarization observed by so many has to be understood in the context of these pronounced asymmetries between the two parties.