What accounts for the widespread support for Donald Trump in the 2016 U.S. presidential race? This experiment demonstrates that the changing racial demographics of America contribute to Trump’s success as a presidential candidate among White Americans whose race/ethnicity is central to their identity. Reminding White Americans high in ethnic identification that non-White racial groups will outnumber Whites in the United States by 2042 caused them to become more concerned about the declining status and influence of White Americans as a group (i.e., experience group status threat), and caused them to report increased support for Trump and anti-immigrant policies, as well as greater opposition to political correctness. Increased group status threat mediated the effects of the racial shift condition on candidate support, anti-immigrant policy support, and opposition to political correctness. Among Whites low in ethnic identification, in contrast, the racial shift condition had no effect on group status threat or support for anti-immigrant policies, but did cause decreased positivity toward Trump and decreased opposition to political correctness. Group status threat did not mediate these effects. Reminders of the changing racial demographics had comparable effects for Democrats and Republicans. Results illustrate the importance of changing racial demographics and White ethnic identification in voter preferences and how social psychological theory can illuminate voter preferences.