In his inaugural address today, Donald Trump promised to “bring back our borders.” The refrain is inaccurate (U.S. borders were not seriously policed until the 1990s and are more policed today than ever before) but it is familiar.

Lately this line has echoed most loudly in Trump country — rural America, particularly the South. But we can’t forget who started it: California.

In recent Op-Ed  pieces, I’ve written about California’s culpability for our current anti-immigrant discourse and reached the conclusion that it was Trump, a New York billionaire, who finally helped nativism conquer the South.

Historians trade in contingency–the idea that while abstract social and economic forces are real and sometimes extremely powerful, individual people and unexpected events can change the course of history. Corazón de Dixie details the social and economic forces that kept Southern power brokers open to (or explicitly encouraging of) Latino immigration through most of the twentieth century. And the electoral success of Trump’s anti-immigrant campaign reminds us how human beings navigate these forces in ways that can be unpredictable.