"American public opinion tends to be sticky. Although the news cycle might temporarily affect the public zeitgeist about abortion, the death penalty, or gun control, public support or opposition on these issues has remained remarkably constant over decades. But there are notable exceptions, particularly with regard to polarizing issues that highlight identity politics. Over the past three decades, public support for same-sex marriage has risen from scarcely more than a tenth to a majority of the population. Why have people's minds changed so dramatically on this issue, and why so quickly? This book tests a theory that when prominent people representing particular interest groups voice support for a culturally contentious issue, they sway the opinions of others who identify with the same group, even if the interest group and the issue at hand have no obvious connection. In fact the book shows that the more the message counters prevailing beliefs or attitudes of a particular identity group, the more persuasive it is. While previous studies of political attitude change have looked at the effects of message priming (who delivers a message) on issues directly related to particular identity groups, this study is unique in that it looks at how identity priming affects attitudes and behaviors toward an issue that is not central or directly related to the targeted group. The authors prove their theory through a series of random experiments testing the positive effects of identity-based messaging regarding same-sex marriage among fans of professional sports, religious groups, and ethnoracial (Black and Latino) groups"--