As the voting public continues to diversify across the United States, political candidates, and particularly white candidates, increasingly recognize the importance of making appeals to voters who do not look like themselves. As history has shown, this has been accomplished with varying degrees of success. During the 2016 election, for example, both Hillary Clinton and Bernie Sanders campaigned vociferously among Latino voters in Nevada's early primary, where nineteen percent of the Democratic caucus consisted of Latinos. Clinton released a campaign message to these voters stating that she was just like their abuela (or grandmother). The message, widely panned, came across as insincere, and Clinton, who otherwise performed well among Latinos nationally, lost by a wide margin to Sanders. On the other hand, in 2013, Bill de Blasio, campaigning for mayor of New York City, appeared with his black son in a commercial aimed against stop and frisk policies. His appeal came across as authentic, and he received a high level of support among black voters. In Campaigning in a Racially Diversifying America, Loren Collingwood develops a theory of Cross-Racial Electoral Mobilization (CRM) to explain why, when, and how candidates of one race or ethnicity act to mobilize voters of another race or ethnicity. Specifically, Collingwood examines how and when white candidates mobilize Latino voters, and why some candidates are more succesful than others. He argues that candidates strategize by weighing the potential costs and benefits of conducting CRM based on the size of the minority electorate (the benefit) and the overall level of white racial hostility (the cost). Extensive cross-racial mobilization is most likely to occur when elections are competitive, institutional barriers to the vote are low, candidates have previously developed a welcoming racial reputation with target voters, whites' attitudes are racially liberal, and the Latino electorate is large and growing. Moreover, candidates who can demonstrate cultural competence and do so repeatedly are much more likely to be successful at making such appeals. The book looks at CRM trends and case studies over the past seventy years to gauge how politics in various places have changed as the American electorate has diversified. It draws on the author's research in over thirty archives in nine states, candidate and survey data, and experimental approaches to assess causality in voter responses to candidate behavior.

The accidental shooting of Kathryn Steinle in July of 2015 by an undocumented immigrant ignited a firestorm of controversy around sanctuary cities, which are municipalities where officials are prohibited from inquiring into the immigration status of residents. Some decline immigration detainer requests from U.S. Immigration and Customs Enforcement. While sanctuary cities have been in existence since the 1980s, the Steinle shooting and the presidency of Donald Trump have brought them renewed attention and raised a number of questions. How have these policies evolved since the 1980s and how has the media framed them? Do sanctuary policies "breed crime" as some have argued, or do they help to politically incorporate immigrant populations? What do Americans think about sanctuary cities, and have their attitudes changed in recent years? How are states addressing the conflict between sanctuary cities and the federal government? In one of the first comprehensive examinations of sanctuary cities, Loren Collingwood and Benjamin Gonzalez O'Brien show that sanctuary policies have no discernible effect on crime rates; rather, anti-sanctuary state laws may undercut communities' trust in law enforcement. Indeed, sanctuary policies do have the potential to better incorporate immigrant populations into the larger city, with both Latino police force representation and Latino voter turnout increasing as a result. Despite this, public opinion on sanctuary cities remains sharply divided and has become intensely partisanized. Looking at public opinion data, media coverage, and the evolution of sanctuary policies from the 1980s to 2010s, the authors show that conservatives have increasingly drawn on anecdotal evidence to link violent crime to the larger debate about undocumented immigration. This has, in turn, provided them an electoral advantage among conservative voters who often see undocumented immigrants as a threat and has led to a push for anti-sanctuary policies in conservative states that effectively preempt local initiatives aimed at immigrant incorporation. Ultimately, this book finds that sanctuary cities provide important protection for immigrants, helping them to become part of the social and political fabric of the United States, with no empirical support for the negative consequences conservatives and anti-immigrant activists so often claim.