MCALLEN, Texas — Along the route through Mexico, no one was really sure how to say Trump’s name. Smugglers called him ‘‘El Malo’’ (the bad one) or ‘‘El Feo’’ (the ugly one) and told the migrants they had better hurry north before his wall went up.
The US agents who took them into custody said he would be president, and it was a new day at the border.
‘‘They said it to the whole group: We would all be deported because Trump won,’’ said Octavio de Leon, 43, a Guatemalan who was detained with his son while crossing into Texas right after the election.
President-elect Donald Trump has promised major change to the US immigration system at a time when Central American families are flowing into the United States in growing numbers, many fleeing warlike conditions and poverty. The US Border Patrol has captured more migrants over the past three months than during the same period in each of the past five years.
Trump has pledged to build a towering border wall and deport millions, proposals that have been sketched out so far only in broad terms.
By winning the election, Trump may have inadvertently made his job even harder. His plans have become a selling point for the smugglers urging people to cross the border before a wall goes up, according to migrants and officials in the United States and Mexico. Others were hoping Clinton would win and offer them some form of blanket amnesty, according to Border Patrol agents. So many families have arrived in recent weeks that US authorities announced last weekend that they are sending 150 agents to shore up this portion of border in the Rio Grande Valley.
Here at the border, the obstacles to Trump’s plans appear daunting. To hold, quickly process, and deport the tens of thousands of arrivals each month, the Trump administration would have to add scores of immigration judges and dramatically expand detention facilities, which have faced legal challenges. A wall could cost billions.
Some here welcome a Trump crackdown. Many Border Patrol agents resent what they see as a ‘‘catch-and-release’’ approach to the flood of Central Americans. To them, Trump’s win has delivered the morale-boosting equivalent of a Red Bull.
‘‘We’re going to be able to do our jobs again,’’ said Chris Cabrera, a Border Patrol agent and a spokesman for their union, which endorsed Trump for president.
‘‘We’ve turned into a detention agency,’’ he said. ‘‘We’re not out there enforcing. We’re doing jailer work and sometimes babysitting.’’
But analysts, lawyers and elected officials on both sides of the border say it is a place that has always defied easy fixes and expensive barriers.
What is often lost in the debate about border control is the dramatic change in who is trying to migrate. The number of Mexicans caught trying to illegally cross has been dropping — from more than 400,000 in fiscal 2010 to about 177,000 this year. Meanwhile the number of migrants from violence-plagued El Salvador, Honduras, and Guatemala has nearly quadrupled in the same period, to almost 179,000.
Many of the Central Americans do not sneak over under the cover of darkness; they are delivered by smugglers to the banks of the Rio Grande and wade across in broad daylight to turn themselves in to Border Patrol. That’s because most of the migrants are asking for some type of asylum and, therefore, are entitled to go before an immigration judge to plead their case, rather than being quickly deported. But it often takes months, if not years, for the backlogged courts to determine whether asylum seekers face danger at home and deserve protection.
In the meantime, most of the migrants are released from detention after a few days. Often, they do not appear for their court dates. Of the 20,000 families whose legal proceedings ended with deportation orders between July 2014 and this August, 85 percent did not show up in court, fueling the perception that migrants are gaming the system and intending to stay in the country illegally.
Border Patrol union leaders want more agents and immigration judges, plus longer detention periods for asylum seekers awaiting court dates. Sending a stern message will discourage future migrants, said Hector Garza, a Border Patrol agent in the Laredo, Tex., sector and a union representative.
‘‘You do have to take some action,’’ he said. ‘‘Right now, it’s out of control.’’
But US courts have already ruled that asylum seekers can’t be held simply to deter other migrants from coming. And ‘‘you can’t get rid of the due-process proceedings,’’ said Lorilei Williams, director of the immigration unit at Staten Island Legal Services, in New York. Asylum applicants are generally entitled to court hearings under international law.
A big increase in judges would take time and money. Representative Henry Cuellar, a Democrat who represents the Texas border and received budgetary approval for 55 more immigration judges in fiscal 2016, said it was unrealistic to think the courts could quickly accelerate their processing of cases.
‘‘Right now, we’re backlogged half a million [cases] with the current judges that we have,’’ he said in an interview. ‘‘Practically, you’re talking about years and years’’ to process those cases.
Two years ago, after a flood of families from El Salvador, Honduras, and Guatemala overwhelmed border authorities, the Obama administration launched a public-relations campaign to discourage migrants from making the trip, stepped up deportations of migrants who were denied asylum, and pressured Mexico to crack down on its own southern border.
Fewer migrants arrived at the US-Mexico border in 2015, but the figures have been climbing this year. Violence and poverty continue to drive people north, along with the election-year factors: Some migrants had expected that it might be more difficult to enter the United States if Trump won. Other hoped that his Democratic rival, Hillary Clinton, would win and offer them some form of amnesty, Border Patrol agents said. In October, Border Patrol apprehended 46,195 migrants, nearly 11,000 more than in the same month during the immigration crisis in 2014.
In McAllen, at the Sacred Heart Catholic Church, which takes in migrants once Border Patrol agents release them for their immigration court appearances, there were days in October when nearly 500 adults and children arrived, forcing authorities to erect tents to house the Central Americans in the parking lot.
‘‘We’ve seen more people show up dehydrated, sick with scabies and chickenpox. We need to get more medical treatment,’’ said Josh Ramirez, McAllen’s health director.
Spikes in illegal migration to the United States occur for different reasons, including misinformation about potential amnesties and fears of a stricter climate in the future.
‘‘I’m sure that the discussion about a wall and getting tough on immigration was used by people down there to say, ‘Get up here now before it’s too late,’ ‘‘ McAllen Mayor Jim Darling said in an interview.
Ever Javier Palma Romero, a 24-year-old fish processor from coastal El Salvador, spent six weeks on the road with his daughter, Jackeline, 4, to reach the US border. Rival gangs control huge swaths of territory in his country, and Palma said he had been beaten and robbed by gang members, who also killed his uncle. In his pocket, he carried a folded copy of a statement that his mother gave to police last year saying two gang members had knocked on the family’s door and threatened to kill him.
‘‘We fled here for a good reason,’’ he said.
Two years ago, the border-crossers were mostly women and children, but a significant number of the families at the church shelter were single men traveling with children. Without the kids, they said, their chances of being allowed to stay would be much lower.
Several migrants who arrived at the Texas border in recent days said that Border Patrol agents taunted them about Trump’s victory and threatened deportation.
‘‘They told me: Trump doesn’t want you here. He’s going to kick you out,’’ said Doris Medina, 43, taking shelter from the rain on a cot inside one of the tents at the church shelter. About 20 other adults and children, many of them coughing, sat around her.
Medina was on her way from Honduras to New Orleans to reunite with her husband. She first came to the United States in 1992, and she had spent most of her adult life in Los Angeles, working in a cafeteria at DreamWorks Studios and making deliveries for Pizza Hut.
Medina won a form of asylum known as ‘‘temporary protected status,’’ but when her mother was diagnosed with cancer in Honduras, she went home without permission and could not return legally.
A smuggler was her only ticket back to the United States, she said, and he had told her that ‘‘I needed to get across before that man won.’’