In Becoming Mexican American (1993), George J. Sanchez wrote about the importance of the frontier in the American imaginary. He argued the frontier (as constructed by Frederick Jackson Turner and others) was the “myopic vision” of Euro-American settlers: a mythology used to depict Western settlers as the conquerers of “savagery” and chaos. By moving West, frontiersmen fueled the United States’ belief in the nation’s boundlessness and its destiny to “become the world's leading nation.”
Simultaneously, Sanchez argued the United States’ border with Mexico rhetorically lacked the same nationalistic potency, since the border instead suggested the limitations of American power. To Sanchez, if the frontier represented the unlimited growth potential of the United States, the border instead symbolized the real limitations demarcating American power.
Reading Sanchez' argument in 2020 is surreal. In the past five years (and especially 2015-2018), the United States-Mexico border was easily and forcefully converted into a violent rhetorical symbol for the consolidation of national strength.
In the wake of the Great Recession, the border was weaponized to represent the United States’ capacity to “protect itself.” Building the wall was about preserving American jobs for American people. It was about preventing “cutting in line.” It appealed to middle-class worries about losing economic advantage, and placated white working class fears they were being left behind. The United States has a long history of scapegoating immigrants, and "The Wall" served as an incredibly effective tool at diverting attention away from the real issue of rising inequality in the U.S.
The nationalistic potency of the border was not based on the United States’ geographic potential for growth, it was about stimulating economic growth for white Americans, continuing American exceptionalism, and protecting the now-built “civilization” of the colonized United States against lawlessness and chaos. The Wall capitalized on economic grievance, projections of nationalistic strength, populist anti-immigrant sentiment (oriented against refugees and the “undocumented”), and historical fears of "violent" indigenous and Latin American cultures.
In the last three months, though, China has emerged as the White House's most central target of political rage (aside from Twitter), so it'll be interesting to see if and how the border (as a symbol of American "strength") continues to influence American political discourse. We'll have to wait and see, but right now, it seems the far-right believes China will be a much more useful foil during the COVID-era.