Supermajorities used to be the norm in American politics, yet today it seems unimaginable that our nation could break hard for one party or the other. But as Adam Jentleson demonstrates in Supermajority, his follow up to the "truly excellent" (Ezra Klein) Kill Switch, periods of stasis almost always break and give way to dominant one-party rule. For most of the twentieth century, Democrats held overwhelming control of Congress-supermajorities so commanding that Republicans could do little more than mimic Democratic positions. These supermajorities didn't just enable sweeping legislation, such as Social Security, but also made that legislation stick. Jentleson argues that today's Democrats let interest groups and activists hold them back from building a supermajority, and that they forget that politicians need to be attentive to public opinion even as they seek to shape it. He shows that the party must learn the correct lessons from the successes of FDR, LBJ, and Barack Obama if they hope to usher in a new liberal realignment and forge lasting change