Jun 15, 2025. “Mexican Americans have a saying here, ‘They didn't cross the border, the border crossed them," said Gaspar Rivera Salgado, director of the UCLA Center for Mexican Studies, to The New York Times. The irony of accusations that Los Angeles has been "invaded" by immigrants is not lost on Mexicans and Mexican Americans. Rivera Salgado pointed out that their historical memory goes back to the invasion of Mexico by U.S. troops (among them, Marines) in 1847, during the Mexican-American War. The treaty that ended that war ceded over half of Mexico's territory, including California, to the United States.