Based on chapters 5–9 of Ian Haney López's Dog Whistle Politics: How Coded Racial Appeals Have Reinvented Racism and Wrecked the Middle Class, how is race used to win the working class vote?

Dog whistle politics is the use of racial undertones to win votes. It is a cold and calculated political strategy employed most often by conservatives in the United States. The result is the further enrichment of plutocrats, as white majorities vote against their own economic interests.
Appeals to race are not explicit, however. Because of the success of the civil rights movement, these appeals to race are in code and below the surface.
An example of this is Ronald Reagan's denunciation of so-called welfare queens. Reagan told the story of a "young buck" buying steak with food stamps as hard-working Americans waited in line to buy hamburger. The "young buck" term implied a healthy black male. By using this language, Reagan engendered hostility against both minorities and a government that gives "handouts." Reagan promised tax cuts because people's hard-earned money should not be given to so-called welfare queens. Indeed, Reagan cut taxes, and the plutocrats became much more affluent.
Lopez argues that this has been a cornerstone of Republicans's political strategy for decades. Mitt Romney employed it with his famous remark over the 47% of Americans who do not pay taxes. Although Romney lost to Barack Obama, he won far more white votes than Obama did.
Lopez argues that this strategy has had a pernicious effect on the country. He believes dog whistle politics have effectively convinced whites to consistently vote for policies that are actually harmful to them, to minorities, and to the nation.

Race and race baiting are used to win the votes of the white working class. The author cites the work of Princeton political scientist Larry Bartels, who has shown that working-class incomes have grown six times as quickly under Democratic administrations than they have during Republican administrations (page 8). Therefore, as the author writes, "dog whistle politics is critical to the GOP's success" (page 8). The Republicans do not generally offer political and economic policies that benefit the working class, so they must sway them with coded racial appeals in the form of what the author calls "dog whistle politics."
The author traces this development back to the 1960s and 1970s, when Richard Nixon first broke apart the New Deal coalition of white northern liberals, Northern working-class people, Southern African-Americans, and Southern Democrats. The Republicans broke apart this coalition, which had held from the 1930s through 1960s, by sewing the seeds of racial division. As the author writes, "it was almost inevitable that most whites would abandon the Democratic Party once it became identified with blacks" (page 26). Nixon used appeals to the white working class such as his opposition to busing that won them over to the Republican Party, and this appeal to the working class through coded racist appeals has continued in the years since. The Republicans and Democrats such as Bill Clinton have appealed to the white working class by disassociating themselves with the concerns of African-Americans and suggesting through coded racist language that African-Americans (and later Arab Americans and Latinos) are the source of crime and national security concerns.