BROWNSVILLE, Tex . — Pfc. Jordan Wilson and Alexis Espinoza Padilla stood 500 miles apart in separate worlds, and yet undeniably were linked by practical and geopolitical forces.

Wilson, 25, and his fellow U.S. soldiers worked in the shadow of the Brownsville and Matamoros International Bridge crossing into Mexico, stretching out 50-foot rolls of barbed concertina wire with a metallic jangle near the banks of the Rio Grande on Sunday afternoon. His green camouflage uniform, helmet, body armor, protective glasses and thick gloves were required by commanders, even if he was working stateside. Just a block away, civilians walked to a Dollar General discount store.

A few hours earlier, Espinoza Padilla, 23, fiddled with a cord connecting his cellphone to a solar-powered battery pack on the outskirts of Santiago de Queretaro in central Mexico. He wore a sweater and had pulled his cap down low to protect him from the sun while waiting for a ride in a truck heading north.

The two 20-somethings are at the center of an issue that could percolate for weeks: the potential arrival of a caravan of thousands of migrants at the U.S. border at a single location and the military’s possible role in dealing with it. 

The Trump administration has dispatched more than 5,900 active-duty troops to the border to buttress U.S. Customs and Border Protection agents processing asylum claims. Federal law and Pentagon policy limit the scope of what the troops can do, although the military has said they could be asked to fly CBP officers in helicopters to less-secure parts of the border if the caravan attempts to enter the country there.

The first group of migrants, meanwhile, decided last week to turn west toward Tijuana and began arriving there Tuesday. They numbered a few hundred on Wednesday. They could disperse into smaller groups, but other caravan groups are still farther away in Mexico and it is unclear where they will go.

On the border, U.S. service members are expected to cede all law enforcement missions to the Department of Homeland Security, adhering to the Posse Comitatus Act and Pentagon regulations. 

But some sort of significant encounter remains a possibility, even as Wilson and some of his fellow soldiers struggle with how to characterize their mission.

“This will kind of be like my deployment here, if you call it that,” said Wilson, who has been in the Army less than two yearsand has not yet been overseas.

Asked what he would call it, he said he wasn’t sure, but would do his job to the best of his ability.

“I shrug,” he said. “I don’t know the answer.”

Wire, the mission's motif

In Texas, images of soldiers stringing concertina wire emerged just before the midterm elections and have become the main motif of the mission. More than 150 miles are available, military officials have said. The Pentagon initially called the operation Faithful Patriot, but disclosed just after the election that it had stripped it of that name amid complaints that it had partisan overtones. The military now simply refers to operations as “border support,” and plans to send the troops home by Dec. 15.

Wilson, of the 887th Engineer Support Company of Fort Campbell, Ky., and his fellow soldiers arrived in Brownsville last week to string the wire between the Matamoros bridge and the Gateway International Bridge, less than a mile northeast. CBP officials said they once found a hole cut in the chain-link fence near the Dollar General, Wilson said, presumably allowing someone to slip into Brownsville.

In response, the Army delivered scores of wooden pallets stacked with concertina. Halfway through the one-mile task, more than 40 of the 50-foot rolls were stacked on each pallet. Wilson looked on as soldiers put about a dozen pallets at a time on a 10-wheel flatbed truck and drove it from a CBP parking lot down a hill that was covered in scrub brush and dying castor bean plants. They parked it on a sandy bank near the Rio Grande.

There, the troops pulled the pallets off the truck on skids, broke them down and got to work. 

“I bet you five bucks we have to take all this down in a few weeks,” one soldier said to a friend while they tied wire. The fellow soldier scoffed at him.

In a statement to The Washington Post, the CBP said the issue is not yet settled.

Defense Secretary Jim Mattis and Homeland Security Secretary Kirstjen Nielsen visited soldiers at the border in Texas on Wednesday. When one asked whether the Army would have to remove the wire, Mattis said: “We’ll let you know.”

Selling smokes to buy a phone

The issue was a long way from Espinoza Padilla’s reality in Mexico.

He and his father left their home in Honduras in fear of the malevolent reach of the MS-13 street gang, which had killed his cousin. Two sisters in Texas, both undocumented, told him he could go back to Honduras but that it was worth trying to reach the United States, he said.

Standing near a highway toll booth Sunday, he prepared to shift west, toward the city of Irapuato, and eventually California. His father, in a red baseball cap, a tan jacket and jeans, wore a yellow wristband from Mexico City, where officials had tried to count a group that seemed uncountable, as nobody one stayed still for long.

Espinoza Padilla said he left home without a phone, but bought one on the road using money he and his father made by selling cigarettes for a peso each — more when people were stressed out. He used the phone to talk to his mother in Honduras and his sisters, at least when he found enough power to do so.

Espinoza Padilla had tried to travel to the United States before, but was deported by Mexican immigration agents, he said. He was trying again now, hoping to reach an official port of entry to apply for asylum and make his case why he should be allowed to stay. He had heard that the border was now lined with armed police, but said he had faith that God would protect him.

“We’re peaceful, so we want to see whether they give us refugee status,” he said. “But it depends on what the judge says — or at least that’s what they told us here in Mexico.”

Watching the watchers

Back in Brownsville, Staff Sgt. Javone Somersall scanned the surrounding area for potential threats. Somersall, a military policeman from the 287th Military Police Company at Fort Riley in Kansas, carried a holstered 9mm M9 pistol. It was light weaponry as military work goes — only the MPs were armed, and none had a rifle.

Somersall had deployed three times to Iraq during a career that started as the United States invaded there more than 15 years ago. Now he was watching the muddy Rio Grande for any crossings from the Mexico side. None had occurred in the last week, but soldiers reported to law enforcement an instance of being watched from the other side of the river, he said. 

Migrants on the bridge also glanced over the edge at the troops below, while a few Border Patrol agents posted on the bridge watched the migrants.

“Every once in a while we make eye contact and let them know we’re coming through,” Somersall said of the Border Patrol.

In Mexico, Veronica Georgina Trochez Castellano and her 14-year-old son prepared to stay the night at the government center in Irapuato. She said she left Santa Cruz, Honduras, last month after her son was nearly recruited by a gang to be a “banderin,” a neighborhood lookout.

Traveling with nine others seemed like the best way for Trochez Castellano and her son to stay safe, she reasoned. The mother-son pair have lost track of the others for days at a time, only to find them again.

Trochez Castellano was worried about her son, but also imagined a better life for herself in the United States in which she would be able to buy some land of her own.

“At 43, there’s no way I can find work, and the government in Honduras is miserable,” she said. 

Trochez Castellano had laid out her cot alongside a fence outside the government center, wedged between a 31-year-old fish farmer and an elderly man, who peeked out of his makeshift tent only to peel an orange.

In the afternoon, Trochez Castellano tied the edges of a blanket to a fence and huddled underneath to avoid the sun. As night fell, the blanket would protect her from the cold. It was not as good as the tents that other people carried. But it would have to suffice.