From Greg Grandin, professor at New York University and author of The End of the Myth: From the Frontier to the Border Wall in the Mind of America (2019):

The wall might or might not be built. But even if it remains only in its phantasmagorical, budgetary stage, a perpetual negotiating chip between Congress and the White House, the promise of a two-thousand-mile-long, thirty-foot-high ribbon of concrete and steel running along the United States’ southern border serves its purpose. It’s America’s new myth, a monument to the final closing of frontier. It’s a symbol of a nation that used to believe that it had escaped history, or at least strode atop history, but now finds itself trapped by history, and of a people who used to think they were captains of the future, but now are prisoners of the past.