Haney Lopez writes that in the aftermath of the terrorist attacks on September 11, 2001, "dog whistle politics surged anew, with much of the hysterical focus shifting from African Americans to brown immigrants, both Muslim and Mexican" (page 115). Therefore, Arabs, Muslims, and Latino were all targets of dog whistle politics in the U.S. after 9/11.
After 9/11, the Bush administration carried out dragnets that targeted Arab Muslims rather than specific individuals, fostering, in the author's words, "the impression that the United States faced a racial threat rather than merely an extremist one" (page 118). In other words, dog whistle politics converted what was a political and security threat into a threat that was racial in nature. While the category of Arab Muslims is not exactly a neat one, as some Arabs do not practice Islam (and many Muslims are not Arab), the category of "Arab Muslim" was simplified in the minds of many Americans as synonymous with terrorists. Bush referred to Arab Muslims in racially coded terms, and he "helped cement the culturally potent image of U.S. society locked in mortal combat with Arab Muslims" (page 119). Bush used coded racist appeals about Muslims and Arabs to rally support after 9/11 and to launch wars in the Middle East.
In addition, conservatives starting with Reagan used coded racial appeals to portray Latino immigrants in negative terms by using the idea of cultural conflict (page 121). For example, Pat Buchanan and others have warned Americans about the loss of American culture and the English language if Mexican immigration continues. While many non-Latino Americans have long engaged in anti-Latino sentiment, this xenophobic sentiment took on an element of heightened emotion after 9/11, as it was equated with national security concerns. By concentrating on illegal immigrants, politicians spread this racist sentiment to all Latinos, even those whose families have lived in the U.S. for decades, if not centuries! These types of sentiment and dog whistle politics are practiced by both Republicans and Democrats alike. In fact, Obama has removed more undocumented immigrants than Bush--more than 400,000 in one year alone (page 123). More than 97% of those deported in 2010 were Latino (page 123), showing that the Democrats are also practicing anti-immigrant practices and using anti-immigrant rhetoric.