Why the wall was built

Summary

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Throughline (NPR): "Why the Wall Was Built"

Date: April 21, 2026
Hosts: Rund Abdelfatah & Ramtin Arablouei
Featured Guests: Anya Steinberg, Christina Kim (Producers); Rachel St. John (UC Davis historian)

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Episode Overview

This episode—part of the limited-run "America in Pursuit" series—explores the little-known history behind one of the first barriers on the US-Mexico border. The story centers on Ambos Nogales, a city literally split by the border, and unpacks how a string of historical turning points transformed a "porous, ambiguous boundary" into a highly surveilled and policed frontier. The episode reveals that walls and fences weren’t first built primarily to prevent immigration as understood today, but to address customs, sovereignty, and incidents of cross-border violence.

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Key Discussion Points & Insights

The Ambiguity of the Early Border

• Ambos Nogales—meaning "both Nogales"—existed as two towns, one in Arizona, one in Sonora, where people, goods, and services flowed freely. The border was poorly marked and more of a concept than a physical divide ([03:09]).
• Local entrepreneurs, like saloon owner John Brickwood, exploited this ambiguity—his establishment sat on the border, allowing tax-free sales of both American liquor and Mexican cigars ([03:23], [03:41]).

Notable Quote

"We speak of the two towns as one, for they are really such being divided by imaginary line only."
—Nogales, Arizona newspaper ([04:24])

Increasing Tensions & Need for Demarcation

• As the town expanded and border towns "got more heavily developed," government agents from both countries found it increasingly hard to know which country they were in ([04:43]).
• A boundary marker—a giant obelisk—was erected on Brickwood's saloon porch in the 1890s, signaling growing interest in clearly delineating the border ([05:12], [05:16]).

Notable Quote

“Customs officers start saying, you know, this is, it's impossible for us to police this space if people can just walk through John Brickwood's saloon."
—Christina Kim ([04:43])

Mexican Revolution & Rising Violence

• The Mexican Revolution (starting 1910) made border towns strategic for both revenue collection and power, inviting raids and increasing instability ([05:58]).
• The instability, paired with World War I fears of German spies, escalated cross-border suspicion, militarization, intelligence gathering, and the first real moves toward physical control ([06:33]).

The Spark: The Battle of Ambos Nogales (1918)

• On August 27, 1918, a deadly misunderstanding involving a Mexican carpenter sparked a gunfight. Customs officials on both sides shouted conflicting orders; a shot was fired (by whom is disputed), leading to over two hours of chaos and violence ([07:39]-[10:18]).
• The conflict was so significant it was immortalized in a Mexican "corrido", a ballad recounting local heroics ([08:43]-[09:52]).

Notable Quote

"There were 1500 gringos, all were federal troops, and the people of Nogales did not let them advance."
—Rachel St. John, translating the corrido ([09:04])

Memorable Exchange

Mexican consul tries to negotiate with an American soldier:
"If they both raised a white flag, it could all be over."
American soldier responds: "Go to hell. American troops don't carry white flags and don't use them."
([10:05])

• The outcome: Four Americans and 129 Mexicans dead, including the mayor of Nogales, Sonora, with hundreds wounded ([10:18]).

Aftermath: The First US–Mexico Border Fence

• Officials on both sides agreed on the necessity: "We need a fence. We need to be really clear about marking this space."
  —Christina Kim ([11:04])
• The initial fence was constructed not as a migratory barrier, but to clearly demarcate territory and reduce tensions ([11:11]).

Notable Reflection

"Whenever I think about this, I think of the Robert Frost poem where he talks about how 'good fences make good neighbors,' right? ... This is not seen as an imposition ... but rather a joint effort to better demarcate where Mexican and American space end."
—Christina Kim ([11:19])

The Shift: From Customs to Immigration Enforcement

• Early fences weren't built to block Mexican migration; in the late 19th century, most U.S. concerns about southern border crossings were directed at Chinese immigrants ([11:53]).
• In 1924, the U.S. Congress significantly restricted immigration, established quotas, and created the Border Patrol—the infrastructures underlying today's border regime ([12:16]).

Notable Quote

"By the mid-1920s, the infrastructure of the border, the fences, the manpower and law enforcement ... the tools that we use today, were all in place."
—Rachel St. John ([12:32])

Modern Echoes

• Today, over 700 miles of border wall exist. The 2025 "One Big Beautiful Bill" under President Trump allocated over $170 billion, aiming to complete the wall by the end of his second term ([12:46]).

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Timestamps & Segment Highlights

• [03:09] - [04:24]: Ambos Nogales’ merged social and economic life; “imaginary line” era.
• [05:12] - [05:16]: Erection of the boundary marker/obelisk on John Brickwood's saloon porch.
• [05:58] - [06:33]: Mexican Revolution; rise in violence, immigration, and smuggling.
• [07:39] - [10:18]: 1918 gunfight; the Battle of Ambos Nogales and its aftermath; the birth of the border fence idea.
• [11:11] - [12:16]: Construction of the first U.S.–Mexico border fence and shift toward immigration enforcement.
• [12:46]: Modern policies and the continuation of border wall expansion.

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Memorable Quotes & Context

• "We speak of the two towns as one, for they are really such being divided by imaginary line only."
  —Nogales, Arizona newspaper ([04:24])

• "So the US sent a survey team to mark the border more clearly. They put a new boundary monument and built it on the porch... A giant white obelisk."
  —Rachel St. John ([05:07]-[05:16])

• "Whenever I think about this, I think of the Robert Frost poem where he talks about how 'good fences make good neighbors,' right?"
  —Christina Kim ([11:19])

• "The fence wasn't about keeping Mexican people out of the U.S.—no one cared about immigration at all on the U.S.–Mexico border until very late part of the 19th century."
  —Rachel St. John & Christina Kim ([11:53]-[11:58])

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Conclusion

This Throughline episode reveals that the wall on the US–Mexico border wasn’t originally about immigration, but about customs control, local tensions, and responding to violence and wartime paranoia. Physical barriers—originally joint, ambiguous undertakings—morphed over decades into rigid symbols and tools of national sovereignty and exclusion. The episode invites listeners to reconsider common assumptions about the southern border by tracing the “wall’s” little-known, multifaceted origins.

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Transcript

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[Rand Abdelfattah]

This is America in Pursuit, a limited run series from Throughline and npr. I'm Rund Abdelfattah. Each week we bring you stories about life, liberty and the pursuit of happiness in the US that began 250 years ago. Last week we talked about the expansion of the United States into a newfound global power. But even as the country was expanding its borders around the world to include places as far away as the Philippines in the late 19th century, it was also limiting what was and wasn't part of the United States by creating boundaries and borders, especially along the border between the US And Mexico.

[Christina Kim]

We need to be really clear about marking this space and that leads a lot of government officials along the border to say we need a fence.

[Rand Abdelfattah]

Today on the show Throughline producers Anya Steinberg and Christina Kim take us to the border city of Ambos Nogales to tell us the story of one of the first walls on the US Southern border. That story after a quick break.

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[Narrator / Storyteller]

We're at a saloon in Southern Arizona known as the Exchange. There's men sitting around drinking and gabbin, just like any old timey Western saloon

[Rachel St. John]

The saloon is in a town called Ambos Nogales. Well, actually it's two towns, Nogales, Arizona and Nogales, Mexico. That's why it's called Ambos Nogales. It means both Nogales and the owner

[Narrator / Storyteller]

of this saloon, John Brickwood, has purposefully built it right on the border

[Christina Kim]

so he could sell American liquor without any duty on it from inside the bar.

[Rachel St. John]

This is Rachel St. John. She's a professor of history at UC Davis.

[Christina Kim]

And then he had a little box on the outside that was actually in Mexican territory. And so he could sell Mexican cigars from the box without having to pay the duties on them there as well.

[Narrator / Storyteller]

For most of the 1800s there wasn't much going on here. The town was mostly railroad workers and the gambling saloons and brothels that served them. The railroad was finished in 1882 and it ran right through Amos Nogales. It brought merchants and traders to the town. The ability to move between the US and Mexico was actually a huge economic draw.

[Christina Kim]

And I think it's important to recognize that these government agencies and the border towns around them are initially made to support trans border movement.

[Narrator / Storyteller]

And things were pretty friendly between Mexico and the US along the border in these early years. A Nogales, Arizona newspaper wrote, we speak

[Additional Narrator / Closing Remarks]

of the two towns as one, for they are really such being divided by imaginary line only as those towns get

[Christina Kim]

more heavily developed, it becomes hard at times, particularly for government agents, but also for regular people to distinguish between when they're in Mexico and when they're in the United States. Customs officers start saying, you know, this is, it's impossible for us to, to police this space if people can just walk through John Brickwood's saloon and we can't see if they're entering the US or Mexico.

[Rachel St. John]

So the US sent a survey team to mark the border more clearly.

[Christina Kim]

They put a new boundary monument and they build it on the porch.

[Rachel St. John]

A giant white obelisk, the new boundary marker smack dab on the porch of the saloon. But that marker was just the first step towards something much larger. In 1897, then US President William McKinley issued a proclamation to create a clear strip of land 60ft wide and 2 miles wide right through Ambos Nogales. The goal, to demarcate the border more clearly. John Brickwood's saloon and several homes and businesses were knocked down. And for a few years the border stayed that way until 1910 when the Mexican Revolution changed life on the border once again.

[Christina Kim]

Border towns became particularly important because they had ports of entry where people pay their customs duties. So if someone can take over a border town, they can take that money.

[Narrator / Storyteller]

Different Mexican revolutionary factions would raid American towns along the border. And as Mexico became increasingly unstable, more Mexicans started emigrating to the US Violence

[Rachel St. John]

along the border increased.

[Narrator / Storyteller]

And then, in the middle of the Mexican revolution, World War I began. That brought a whole new set of anxieties.

[Rachel St. John]

The US feared that German spies could infiltrate through the border. All of a sudden, people who had long been neighbors were suspicious of each other.

[Narrator / Storyteller]

The US started to send all kinds of people to the border to address these different threats.

[Christina Kim]

The US government deploys the military to the border to protect people on the US side. You also have intelligence officers operating on the border looking out for spies, more customs agents coming out, trying to watch for smuggling of guns and money. And then you have immigration officials who are trying to manage the flow of refugees.

[Rachel St. John]

Those big changes on the border were coming to Ambos Nogales too. The mayor of Nogales, Mexico ordered construction of a wire fence on the Mexican side to make it easier to manage the flow of crossings. But Ambos Nogales had already become a powder keg.

[Narrator / Storyteller]

And on August 27, 1918, the fuse was lit.

[Rachel St. John]

It was just after 4:00 in the afternoon. A Mexican carpenter named Teferino Gila Madrid was leaving the US after finishing work. He was carrying a bulky package under his arm. As he approached Mexico, he was ordered

[Christina Kim]

to halt by American officials.

[Rachel St. John]

They wanted to inspect the package.

[Christina Kim]

Mexican officials told him he should keep coming.

[Rachel St. John]

The U.S. customs official raised his rifle to force Gila Madrid to come back for an inspection. What happened next is still disputed today.

[Narrator / Storyteller]

Someone from either side of the border, it's unclear who fired the first shot.

[Christina Kim]

And violence broke out, actually between the two sides of the border.

[Narrator / Storyteller]

It was chaos. Mexican civilians grabbed guns and joined the fight.

[Rachel St. John]

It's immortalized in this Mexican song,

[Christina Kim]

Tells

[Rachel St. John]

the Mexican version of the battle. The song goes, when a Mexican crossed the borderline, a gringo fired a shot at him. That was the beginning of the story. To Corrido is all about the bravery of the Nogalences. It says. There were 1500 gringos, all were federal troops, and the people of Nogales did not let them advance.

[Narrator / Storyteller]

But things were escalating. At some point, a Mexican consul tried to negotiate with an American soldier. If they both raised a white flag, it could all be over. The American replied, go to hell.

[American Soldier (Reenactment)]

American troops don't carry white flags and don't use them. If the Mexicans don't hoist a white flag within 10 minutes, US soldiers will march in and burn. Nogales, Sonora.

[Narrator / Storyteller]

The Mexican side raised a white flag. The battle lasted more than two hours. As many as four Americans and 129 Mexicans were dead, including the mayor of Mexico's Nogales. And hundreds of people were wounded.

[Rachel St. John]

After the battle of Ambos Nogales, people on both sides expressed regret.

[Additional Narrator / Closing Remarks]

The shooting was an unfortunate affair started by irresponsible persons under undue stress of

[Narrator / Storyteller]

excitement, but the damage was done.

[Christina Kim]

And that leads a lot of government officials along the border to say we need a fence. We need to be really clear about marking this space.

[Rachel St. John]

And so one of the first US Built fences meant to divide people was built through Ambos Nogales.

[Christina Kim]

Whenever I think about this, I think of the Robert Frost poem where he talks about how good fences make good neighbors, right? That these fences are built in a very different mindset than the border wall of today. This is not seen as an imposition by the US Government on Mexico, but rather a joint effort to better demarcate where Mexican and American space end.

[Rachel St. John]

The fence wasn't about keeping Mexican people out of the U.S. no one cared

[Christina Kim]

about immigration at all on the U.S. mexico border until very late part of the 19th century.

[Rachel St. John]

And if people were concerned about who was coming through the southern border, that concern was mostly about Chinese immigrants. Which isn't to say immigration wasn't a big issue in the U.S. it was.

[Narrator / Storyteller]

In 1924, Congress passed one of the most restrictive immigration laws in its history, setting strict quotas for who can enter the US Congress also established the Border Patrol to control immigration.

[Rachel St. John]

By the mid-1920s, the infrastructure of the border, the fences, the manpower and the law enforcement, the tools that we use today, were all in place.

[Rand Abdelfattah]

Today There are over 700 miles of border wall between the US and Mexico. In 2025, President Trump's One Big Beautiful Bill act allocated over $170 billion over four years towards increasing immigration. En roughly 50 billion of those dollars are intended for new construction and reinforcement of the border between the US And Mexico. The administration has said it aims to complete the entire southern border wall by the end of President Trump's second term. That's it for this week's episode of America in Pursuit. If you want to hear more about the first border wall, check out the full length episode line Fence Wall, which is a part of our larger series on how immigration enforcement became political and profitable. And join us next week when we go back and look at the people in America who were literally fighting for change from within there's this idea that

[Historical Voice / Jack Johnson Segment]

the whole community is invested on this. If Johnson wins, the Negroes around the country are going to riot. They're going to revolt. They're going to get the idea that they can fight back. They're going to get the idea that they're not inferior.

[Rand Abdelfattah]

The story of Jack Johnson, the first black American heavyweight boxer in the world, who fought for much more than a title. Don't miss it. This episode was produced by Kiana Moghadam and edited by Christina Kim, with help from the Throughline production team. Music as always by Ramtin and his band Drop Electric. Special thanks to Julie Kane, Irene Noguchi, Beth Donovan, Casey minor and Lindsey McKenna. We're your hosts, Rand Abdelfatah and Ramtin Arablouei.

[Additional Narrator / Closing Remarks]

Thank you for listening.

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