Construction may never begin on President Donald Trump’s proposed wall along the border with Mexico, but it doesn’t really matter because it’s already quite a successful barrier.

Beyond the nearly 700 miles of existing “security fencing,” the president’s imaginary and contentious wall has built up—or reinforced—so many prejudices in the larger national consciousness that it’s difficult to believe there isn’t already an enormous slab of concrete separating the United States from the southern border.

Indeed, if the long list of social ills that Trump blamed on undocumented immigration in last week’s State of the Union is anything to go by—fewer jobs, lower wages, overburdened public services, increased crime, drug abuse, and gang violence—the mental barriers have been erected.