Compromise is critical to democratic policymaking, but it can be hard to find on Capitol Hill.In this era of normalized gridlock, however, some politicians do still cross the aisle.In Dealmakers, David C. Barker, Andrew M.O. Ballard, and Christopher Jan Carman examine when this occurs and why the politicians that do so tend to be Democrats.The answer, the authors contend, comes down to partisan differences in personality and values among voters.Specifically, they suggest that empathetic traits and values drive Democrats to accept compromise, whereas competitive traits and values drive Republicans to reject it.As the authors show, these differences can filter up through the ballot box to the halls of Congress.Drawing on evidence from opinion surveys, randomized experiments, Twitter, and legislative transcripts, Dealmakers evaluates the train of openness, altruistic values, and other political and psychological factors that play a role in political compromise.