How the U.S.-Mexico border was created, changed and enforced

Patrolling the border
A vehicle drives along the U.S.-Mexico border fence at sunset in an area where activists opposing illegal immigration search for border crossers near Campo, California.
Photo by David McNew/Getty Images

What began in 1848 as a line drawn in the sand, has over the years been transformed into an increasingly regulated boundary.

President Trump had continued his call to build a wall separating the U.S. and Mexico, as a tool of getting immigration and drug traffic back under control.

However, there has never a time when the border was under control, said historian Rachel St. John.

"The way that I can best explain what both the U.S. and Mexican governments are trying to do on the border, is that their goal is always to create what I like to think of as a conditional border," said St. John during talk given in St. Paul on Feb. 25, 2017, at the Minnesota Historical Society's "History Forum." They want some people and goods to come through while completely stopping others; and it's not a wall or fence that keeps these things in or out, it's the law, she said.

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As a white woman, St. John said she will encounter a much easier time crossing the border at a checkpoint than a Guatemalan laborer.

"That has nothing to do with the fence being any different, we're both encountering the same physical landscape."

Fences and checkpoints instead should be thought of as symbols of where that jurisdiction begins, she said.

"It's worth noting that the first border fence was actually not built by the government to control the movement of people, but rather the movement of cattle," St. John said.

And when the government did build other fences they weren't to keep people out, they were to signify where it was legal for the U.S. military to shoot trespassers.

As time went on more fences were built to funnel immigrants to checkpoints, though they were often cut and rendered useless by those entering illegally. In the 1990s, sensors were added to some areas to make what was called a "virtual fence," though this too was not a perfect solution. It was an expensive process, caused problems with local landowners and didn't have a large effect on immigration, St. John said.

The current presidential administration is again attempting to build more physical barriers at the border in what St. John says is "part of a pursuit, at least in terms of political rhetoric, of a mythical controlled border that has never existed."

St. John is professor of history at the University of California-Davis. She's the author of "Line in the Sand: A History of the Western U.S.-Mexico Border."

To listen to the speech, click the audio player above.

Further reading

• January: Trump moves to build border wall, cut sanctuary city funds

• On the border: Trump's wall met with skepticism, unease

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