Just the mention of it can raise hackles in Arizona. Sometimes it seems as if it has always been a part of our political debate and existence in the Grand Canyon State, and it feels like there are only two reactions — love it or hate it.

But the now-familiar 18-foot, closely spaced bollards (or vertical metal poles) that make up most of the current wall are a relatively new sight, as is the lighted gravel road running next to it on the Arizona border. For much of the state’s history the border was a porous barrier, filtering out cattle and marking the international boundary, but not stopping people or anything else.

Since the Gadsden Purchase in 1853, the U.S-Mexico border has been in its current location, stretching across 372 miles of Arizona desert and passing through Yuma, Nogales, and Douglas. Until 1918, there was no border fence at all. In Nogales, the border was marked by an invisible line down the middle of International Street.

In a 2010 academic paper published by the Arizona Historical Society, Carlos Francisco Parra related the story of the Battle of Ambos Nogales, which sparked the construction of the first border fence in the state. As the Mexican Revolution raged to the south and World War I exploded in Europe, tensions grew high in Nogales in 1918.

New restrictions were in place for Mexicans coming into the U.S., including how often they could cross and what they could take back to Mexico. Scarcity in Mexico had forced residents south of the line into the U.S. for food, and when the U.S. government restricted food exports, the stage was set for an altercation. National Guard units trained U.S. citizens and sold them cheap rifles and handguns in preparation for conflict. Soldiers were posted along International Street to control cross-border traffic.

As anger over the new laws rose in the binational city, Parra wrote that two people were shot and others arrested for illegally entering the U.S., though the level of summer violence never rose above a simmer.

Then on Aug. 27, a gunfight erupted on International Street between Mexican and U.S. troops.

“A carpenter named Zeferino Gil Lamadrid, a well-known resident of Nogales, Sonora, was leaving the United States after finishing his day’s business. He carried a bulky package under his arm as he crossed the international border at the railroad customs kiosk, near the present-day Grand Avenue Port of Entry, in downtown Nogales, Arizona,” Parra imparted.

“Gil Lamadrid had already stepped onto Mexican soil when U.S. Customs Inspector Arthur Barber, suspicious of the parcel, ordered him to stop and return for inspection. Only a few feet away, Mexican celadores led by Francisco Gallegos directed him to ignore the summons and stay put in Mexico.”

Someone — no one knows who — then fired a single shot. Gil Lamadrid dropped to the ground, thinking he was the target.

Mexican troops, believing Gil Lamadrid had been shot, opened fire at U.S. troops. A running battle then erupted for the next 24 hours in the streets and hills around the towns with a combined population of about 8,000. At least two people, including the mayor of Nogales, Sonora, who was trying to surrender, were killed and several wounded before diplomacy ended the battle.

After the battle a fence was permanently installed.

“The border fence erected in 1918, figuratively and literally separated the two cities.

Where Ambos Nogales had previously been divided only by a wide avenue that everyone could freely cross, a fence now restricted the flow of human traffic across the line,” Parra noted.

Tony Estrada, 77, retired last year after 54 years as an Arizona border law enforcement officer. From 1966 to 1993, he was a Nogales police officer; from 1993 to 2020 he was the Santa Cruz County Sheriff. He has lived his entire life in the shadow of the wall and spent his whole career dealing with it.

Estrada was born in Nogales, Sonora, in 1943, then came to Nogales, Arizona, with his family when he was 18 months old. At that time, Estrada says, crossing the border was easy. His father came freely to look for work, then with little more than a letter of employment, was able to bring his wife and children permanently.

Estrada grew up about three blocks from what was is now the DeConcini Port of Entry, known then as the Grand Avenue Port of Entry. When he was a child and young adult, the fence was a patchwork of chain link in Nogales and a simple barbed-wire fence or nothing at all out in the desert, he recalls.

Opposite page top to bottom: In 1899, the boundary between Nogales Arizona and Nogales Sonora ran down the center of a wide avenue. Wikimedia Commons; U.S. Army and Mexican soldiers pictured at the Nogales border during the Mexican Revolution (1910-1920). The border marker still stands today. Wikimedia Commons; A map of the Gadsden Purchase (1854). Library of Congress Map Division.

As a young man, he was rarely asked anything at the border, though he kept his immigration papers handy when he crossed. People generally were not questioned. Much like the Tohono O’odham Nation, where tribe members could cross at will on tribal land, people could come and go mostly whenever they wanted.

With crossing so easy at checkpoints, there was little need for a wall. The fence that was there was more of a demarcation than a way to stop people, Estrada observes.

“It was not necessarily a deterrent, because it was full of gaps in the downtown area. You could actually walk through it standing up. People would come over, and they would shop. They didn’t have a crossing card, a visa, because either they couldn’t afford one or they didn’t feel they needed one,” he says.

As a police officer in the late 1960s, Estrada spent a lot of time monitoring the fence, but not because of illegal immigration. In addition to shoppers, shoplifters and burglars came across easily.

“Cross-border crime was the biggest concern in the city of Nogales, because (the fence) was wide open at that time. The fence was not a threat. It was not a menace in any way. All of that started changing in the mid’90s. That’s when we started seeing more people come across, and they started fixing up the fence, mostly in the urban areas,” Estrada says.

At one point the urban border fence was made from metal surplus helicopter landing pads from Vietnam, which residents didn’t like because they blocked cross-border communication between friends and family. After that, a metal grid was tried, which allowed people to see each other and talk through the fence. But people started cutting small holes in it, too small to come through or pass large amounts of drugs.

“What they found out was that people were using them for barbecue grills,” Estrada notes. “So the government said, ‘That is not going to work.’” As the U.S. government made the wall more difficult to get through or over, cartels started a new tactic — coming under it. The first drug tunnel in Nogales was found in 1990, Estrada says. Since then, more than 100 have been found in Arizona, including one built by Sinaloa cartel leader Joaquín “El Chapo” Guzmán in Douglas with a hydraulic lift under a pool table.

When the federal government strengthened the border in Arizona’s urban areas, drug cartels and immigrants were pushed out into rural areas to cross. At the same time, hundreds of thousands of people started pouring into Arizona every year, reaching a peak in 2000, when border agents caught more than 720,000 immigrants and smugglers in the Tucson and Yuma sectors.

As of spring, about 135,000 people have been apprehended in Arizona. Along the entire southern border, the Border Patrol is on a pace to apprehend more than 1 million people this year, which hasn’t happened since 2006, when 1.6 million border crossers were apprehended.

Eileen Díaz McConnell, an Arizona State University professor of transborder studies, pointed out that the evolution of the border fence in Arizona is linked to what happened in San Diego in the 1990s, when the Border Patrol began squeezing immigrants into tighter and tighter areas, eventually into Arizona.

In 1996, Congress passed the Illegal Immigration Reform and Immigrant Responsibility Act, mandating construction of a border fence. The law also waived environmental laws to allow expedited construction. It was eventually a game-changer, though construction didn’t ramp up at first because of opposition to the waivers.

Then in 2006, Congress passed the Secure Fence Act, authorizing construction of more than 650 miles of fencing with a 100yard operational zone on the U.S. side. Stretches of barbed wire in the desert were replaced with 18-foot steel bollards filled with concrete and topped with floodlights.

By 2011, the roughly $6 billion project was 99 percent complete.

The construction of that fencing, which started during President Bill Clinton’s administration, marked the beginning of major environmental impact, because fencing went up in remote, sensitive areas, says Laiken Jordahl, borderlands campaigner for the non-profit Center for Biological Diversity.

“Under the Bush administration is when we really started seeing just how damaging border walls can be. We saw walls go up through places like the Buenos Aires National Wildlife Refuge and the Lower Rio Grande Valley National Wildlife Refuge in Texas,” Jordahl says.

Migratory routes for deer, jaguars, pronghorns, and other animals were blocked. A herd of bison, endangered in Mexico, was split by the wall, leaving some on the U.S. and some on the Mexican side. Then the Trump administration brought wall construction to even more remote areas with a taller design with more lights, cutting off more wildlife corridors, Jordahl observes.

“Once you build a wall, wildlife can’t migrate. It doesn’t matter if that wall is 18 feet or 30 feet tall, because the wildlife fragmentation is very similar, although the cactus ferruginous pygmy owl and some other birds have a hard time making it over taller barriers,” he remarks.

Jordahl considers current gaps in the wall, left by canceled construction, a blessing. He recently watched a white-tail deer jump across the border through a gap bulldozed for the new wall.

“That was such a remarkable moment, because that was the very area where the wall was supposed to go up but didn’t because President Biden cancelled the contracts,” he observes.

Vernon Jose is a former vice-chairman of the Tohono O’odham Nation, a Native-American tribe whose land is split by the border. When the federal government designated 4,460 square miles in Arizona for the tribe’s reservation, it left the border open to tribe members, who can cross through a simple gate to and from Mexico.

When the Trump administration ramped up wall construction, it included pushing the wall into remote, sacred areas on the tribe’s land. Citing the Berlin Wall, Jose said walls simply don’t work and this one is a waste of billions of dollars of taxpayers’ money.

“When they cut through our land it was like a knife was dragged across my heart. That’s what happened to America when they put the wall on the sacred sites and the burial grounds,” he said during a recent news conference.

The border is more controlled now than it was in the 1990s or mid-2000s. It is not in crisis, according to a senior border patrol official who talked on background to reporters in late March. The Border Patrol has seen surges in border traffic before, he says.

In addition to a better wall and technology like motion detectors, drones and long-range thermal cameras, the Border Patrol now has four times as many agents as it did in the 1990s. In 1995 the agency had 4,945 agents nationwide with 4,388 on the Mexico border. By 2019 the ranks had swelled to 19,648 nationwide and 16,731 on the southern border.

“The U.S. has never been more secure, when you consider the militarization and surveillance,” Díaz McConnell mentions.

While politicians debate the merits, the Border Patrol measures the effectiveness of border walls. In a case study of the Yuma and Tucson sectors that served as his master’s thesis, Justin A. Bristow, deputy chief of Border Patrol Strategic Planning & Analysis, offered a formula weighing how long it takes agents to arrive against how fast border-crossers enter the country and disappear.

“If detection and response is less than crossing and vanishing time, it is successful and is an indicator of improved operational control. The study of both sectors does show that a wall is effective in some locations but is a much lower priority in other border zones due to a lack of activity, greater response time available to agents, terrain, and fiscal responsibility,” Bristow wrote.

His suggestion was to continue to improve Arizona border fencing built after 2007 in urban and high traffic areas, but leave remote areas, where there is less traffic, alone. The border wall makes more economic sense in Arizona than Texas, where each mile of wall cost three times as much, Bristow concluded.

“The ability to have immediate detection and improved officer safety will allow agents to respond quicker to make an arrest. Improved effectiveness rates will reduce activity and decrease detention and transportation costs,” he wrote.

In a 2017 executive order, President Donald Trump mandated complete operational control across the entire border, something Bristow said has been called, “an aspirational end state unlikely to be achieved unless an impenetrable barrier is designed and constructed along the United States’ international boundaries.”

From the beginning Estrada was against the razor wire National Guard members hung on the Nogales fence during the Trump administration. As sheriff he spoke out against what he called an “atrocity” in a Border Patrol meeting with Arizona’s other border sheriffs. He asked when they were going to take it down.

“I told them in front of that group, ‘We treat livestock better than we treat human beings. You do not put razor wire on livestock fences to keep them out, and you’re doing it with human beings.’You can imagine the reaction. It was real quiet. Nobody said anything.”

Trump’s attempts to bypass Congress to fund a wall have been partially thwarted. President Biden paused all construction shortly after taking office and in April canceled the former president’s diversion of Department of Defense funds for wall construction.

But hundreds of eminent domain cases and numerous government contracts remain in limbo, and hundreds of prefabricated wall sections have piled up undelivered at Stinger Bridge and Iron near Coolidge.

Díaz McConnell called the border wall a permanent solution to a temporary problem, noting that it’s a mistake to assume that reducing border security will automatically lead to an increase in illegal immigration. Legal immigrants outnumber those who cross the border outside the check points, she said.

“Estimates suggest that two-thirds of undocumented immigrants are over-staying visas, and a wall isn’t going to stop that,” she said.

The wall is a reaction to shifting sands. How people come into the U.S. will change, as will the number of people coming, she commented, adding that we catastrophize migration even though it’s relatively rare. Only about four percent of the human population migrates, but that four percent will always be there. Trying to stop it is like squeezing a balloon.

“People find a way. If it’s impossible to cross in one place, they find another place, and that’s what we’ve been seeing all over the world with people dying in bodies of water,” Díaz McConnell noted.

Estrada considers the border wall a mixed bag. It deters drugs and other contraband, but it also divides a city. The two sides of the line are inextricably linked physically, culturally, and economically, and as a Mexican consul once told Estrada in a meeting, the wall doesn’t just divide people. It also unites them.

“And it does. It unites us in the challenges we face, and it unites us in the opportunities we have,” Estrada concludes. TL Special thanks to The Journal of Arizona History for permission to reprint portions of Carlos Francisco Parra’s Spring 2010 article, “Valientes Nogalenses: The 1918 Battle Between the U.S. and Mexico that Transformed Ambos Nogales”.