lick here for larger image. Illustration Frank LeClair.

The Democratic Party has a white problem. In 1990 whites were just as likely to favor Democratic candidates for Congress as they were Republicans. But in 2014, 62 percent of whites voted Republican. Democrats do especially poorly with the type of white voter that used to be their bread and butter—those with less than a college degree.

The transformation of the white vote has many roots. Observers have rightly pointed to the influence of the religious right and the economy as well as the impact of foreign wars, terrorist threats, and climate change politics.

But the data suggest that the Democrats’ immigration platform is also driving the defection. Or, more accurately, the narrative surrounding that platform is drawing voters away.

The growing presence of immigrants has been linked to a host of pernicious fiscal, social, and cultural consequences. Our study of all New York Times articles touching on immigration between 1980 and 2011 indicates that negative stories outnumbered positive stories by four-to-one. Thanks in part to this narrative of threatening immigrants, polls by CBS News and others indicate that an overwhelming majority of whites view illegal immigration as a serious problem. Well over a third think immigration is a bad thing for the country.

The result is that there is now a tight relationship between voting and views on immigration. In last year’s midterms, 75 percent of Americans who felt that most illegal immigrants should be deported voted Republican. Only 35 percent of those who would offer undocumented immigrants a chance to apply for legal status supported Republican candidates.

But is this all correlation without causation? To answer that question, we looked at whether individual attitudes on immigration at one point in time predict changes in future partisanship. The answer is yes. The effect is not large, but small individual shifts in partisan allegiance repeated over the course of decades can become massive electoral shifts over time.

The narrative of immigrant threat is a false one. Most immigrants are not, as claimed, a burden on the social safety net. Most pay taxes, work hard, and are here to benefit from the U.S. economy by contributing to it. The overwhelming majority have committed no crime save crossing the border. If Democrats continue to surrender voters on this issue, their electoral losses will represent the triumph of bias over fact.