Migrants line up as they wait to be processed by US Border Patrol officials after illegally crossing the US-Mexico border in Yuma, Arizona, in the early morning of July 11, 2022.
CNN  — 

There’s a major detail missing from many conversations about the rising number of migrants coming to the US-Mexico border.

Decades ago, the vast majority of migrants attempting to cross the border between ports of entry were Mexican. A few years ago, most came from the Central American countries known as the Northern Triangle: Guatemala, Honduras and El Salvador.

But now, according to Border Patrol statistics, the number of people coming from outside those places – from countries such as Cuba, Colombia, Nicaragua and Venezuela – is growing fast.

David Bier calls it a “radical shift” and a “new phenomenon that no one is talking about.” Bier, the associate director of immigration studies at the Cato Institute, pointed out this change in a recent thread on Twitter. It’s a telling detail, he says, that reveals a lot about what the Biden administration is facing at the border, and why the situation has been so difficult to solve.

To better understand this trend, CNN dove into the data. Here’s a look at what we’re seeing, why this change is so significant, why it’s happening, what this looks like on the ground and what could happen next.

What we’re seeing: There’s a big change in who’s coming to the US-Mexico border. A large number of migrants from Mexico and the Northern Triangle are still making the journey. But the number of migrants from other countries, represented here in purple, has significantly increased.

Back in 2007, the number of migrants in this “other” category was negligible. But since then, it’s grown dramatically — 11,000% — with the sharpest increase in just the past two years.

US Border Patrol encounters still show more migrants from Mexico attempting to cross the Southwest border in July than from any other individual country. But so far this fiscal year, for the first time, encounters with migrants from outside Mexico and the Northern Triangle are outpacing encounters with migrants from either of those regions.

A handful of countries make up a large portion of this growing group at the border. The number of times US Border Patrol officials at the Southwest border encountered migrants from Cuba, Colombia, Nicaragua and Venezuela has increased dramatically over the past two years.

One word of caution about the numbers: For this analysis, we used US Customs and Border Protection statistics on Border Patrol encounters – which include both migrants who are apprehended and detained, at least temporarily, at the border, and migrants who are immediately expelled to their home countries and Mexico. This data gives us the best overall picture of who is arriving and what’s happening at the border.

But officials have acknowledged the numbers can be inflated, because they include some migrants who were turned back under the “Title 42” public health policy, then tried to cross again. In other words, the same people can be counted multiple times.

This is an issue that mostly affects migrants from Mexico and the Northern Triangle, who are more likely to be subjected to Title 42 restrictions than migrants from other countries.

Why this is significant: Doris Meissner, who directs US immigration policy work at the nonpartisan Migration Policy Institute in Washington, says the rise in additional nationalities at the border “makes border enforcement all the more complicated.”

For decades, many border policies have been designed with Mexican migrants in mind, she says, but it’s much more difficult to deport people to other countries. There are limits to which nationalities can be turned back under Title 42, for example. And frosty diplomatic relations can affect deportations, too.

“These populations … require different kinds of responses,” Meissner says. “We have not established an asylum system that is in any way up to the level of the challenge that this change brought about.”

Bier says the groundwork for the trend was laid during the Trump administration. But the situation President Joe Biden is facing at the border is different from anything previous administrations have encountered.

“What he’s dealing with, in terms of trying to restrict entry to the country, is completely different than what any other president has had to deal with,” Bier says. “Those realities are not really reflected in just the overall numbers. Looking at the number of people crossing, it’s just not representative of the unique circumstances of having to handle flows from so many different countries and many countries outside of this continent.”

Administration officials argue they’re working hard to address the root causes of migration. And Biden has described it as a “hemispheric challenge.”

But Bier says officials aren’t doing enough.

“The Biden administration can’t respond to this new reality with the same old playbook,” he said on Twitter. He told CNN that’s exactly what the administration seems to be doing. “It’s a lot of the same types of responses,” he says.

Why it’s happening: There’s no simple reason why this is occurring, Bier says.

“There are as many answers,” he says, “as there are countries represented in that group.”

CBP Commissioner Chris Magnus recently told CBS News it’s impossible to pinpoint all the factors driving migrants to make the journey, given how complicated situations are in their home countries. “It’s a very complex set of dynamics,” he said.

Meissner, who served as commissioner of the Immigration and Naturalization Service from 1993-2000, says the pandemic has played a major role by intensifying economic pressures.

Other factors are also at play. An increase in Cubans making their way to the US, Meissner says, can be partially attributed to a new air route between Cuba and Nicaragua. CNN’s Patrick Oppmann reported that after Nicaragua dropped its visa requirements for Cubans, people began posting online ads selling their homes with “everything inside” to pay for the expensive airfare.

Deteriorating economic conditions, food shortages and limited access to health care are increasingly pushing Venezuelans to leave, and a growing Venezuelan community in the United States is also a draw, Meissner says.

For Colombians and Nicaraguans, economic instability – compounded by the pandemic — has been the main driver of migration, she says, but politics are also playing a role.

Rising repression under the Ortega regime, especially during the recent presidential election, has cemented the belief among many Nicaraguans that the country’s political turmoil will not be resolved in the short term,” Meissner says.

And those who previously saw neighboring Costa Rica as a destination, she says, are more likely to look elsewhere due to decreasing job prospects there.

Rising inflation and unemployment in Colombia are fueling more migration, Meissner says. Social unrest after a wave of protests in 2021 and political divisions that intensified during the recent presidential election are also likely influencing migrants’ decisions, she says.

What this looks like on the ground: This isn’t just something we can see with statistics. Both migrants and Border Patrol officials say they’re noticing the shift.

02:55 - Source: CNN
More Cubans than ever are leaving the island. See where they're going

Yuma Border Patrol Sector Chief Chris Clem told CNN’s Priscilla Alvarez last month that the large number of nationalities crossing the border was straining his agents.

“The countries we’re receiving now — those nationalities are flying in, arriving to the border, and they’re having to be processed and there’s just so many of them that it is posing a challenge to the workforce,” he said.

Speaking to CNN earlier this year, one Cuban migrant described a house in the Mexican desert where she’d waiting with others to cross the border.

One room was packed with Cubans, she said. And another was full of people from different countries.

“There were Colombians, Bangladeshis, Venezuelans, Nicaraguans, Haitians,” she said. “It felt like the whole world was in there.”

What could happen next: Like everything connected with the border, there’s a lot of debate about what officials should do about this.

Biden administration officials have repeatedly emphasized that the border is not open. But those who favor increasing immigration restrictions argue that administration policies have incentivized more people to try their luck at crossing the border illegally. Some – including more than 50% of Republicans, according to a recent NPR-Ipsos poll – say they believe it’s completely true that the “US is experiencing an invasion at the southern border.” And some Republican candidates are emphasizing this message as midterm elections loom, pledging they’ll do more if elected to crack down on illegal immigration.

Bier and Meissner say the changing makeup of migrants at the border shows how badly the US immigration system needs an overhaul.

“Many, if not most, of these people are not likely to be eligible for asylum, even though they’re fleeing very difficult conditions,” Meissner says. “We desperately need to have Congress address the immigration laws and make it possible for there to be other legal pathways to come to the US.”

And countries across the Western Hemisphere need to work together and address migration as a shared responsibility, she says.

So far, there’s no sign this trend is slowing down. And Bier and Meissner say they don’t expect it will.

“It’s entirely plausible to think that this could continue for many years,” Bier says, “because we don’t have the infrastructure to expel people as fast as they come in.”