In a gusty, open-air bus depot in Brownsville, Texas, Febe Carillo-Ramos speaks easily after a journey of hundreds of miles from her home in Guatemala: for the first time in 20 days on the road, she can now move without worry.
Her three-year-old son Wuermer on her lap, she shows a document given to her the day before by the US Customs and Border Patrol (CBP) that allows them to travel to Houston where her husband is, to settle and work, without immediate threat of deportation.
"They told me that with these papers I can go anywhere," the 29-year-old says.
It's the new normal for migrant families under President Joe Biden, after the harsh "zero tolerance" approach of Donald Trump dashed the dreams of hundreds of thousands hoping to escape endemic poverty and violence in Central America.
Biden's pledge of a more humane approach has helped spark a new rush to the border -- and is threatening to become a huge political liability at home.
Republicans are accusing him of opening the country's doors to illegal border-crossers and sparking a "crisis" on the US-Mexico frontier, marked in Texas by the meandering Rio Grande.
They say Biden's easier approach toward immigrants will exacerbate Covid-19 and let "terrorists" in, as House Republican leader Kevin McCarthy claimed Monday.
The mounting criticism saw Biden tell migrants bluntly: "Don't come over ... Don't leave your town or city or community," during an interview with ABC News on Tuesday.
In Brownsville, a loosely-packed city of 180,000 located about 20 miles (32 kilometers) west of where the Rio Grande ambles into the Gulf of Mexico, there is no sense of crisis.
Under cover of dark migrants like Carillo-Ramos cross the river from Mexico with their children, and then turn themselves in to the Border Patrol.
They believe that if they get a foot on US soil, Biden will let them stay.
And while CBP said it sent back many of the 100,000 migrants caught trying to enter in February -- most of them single adults -- hers is a good bet.
For families, mainly mothers with small children, the policy in the Brownsville area is "catch and release."
And every days dozens like her legally board buses to wherever they want to go in the United States.
Also guaranteed able to stay are children who cross the border without parents.
According to social workers in Matamoros, the Mexican city opposite Brownsville, the kids are brought by parents or relatives to the border and sent across alone, some as young as six.
Once across, they too are processed by CBP, and then handed over to the Department of Health and Human Services, which helps them connect with family contacts inside the United States.
But their numbers are overwhelming the system. In February the CBP picked up 9,457 unaccompanied children along the frontier.
According to media reports, currently more than 12,000 are in government hands awaiting settlement.
That is a sharp turn from Trump's approach.
Aiming to deter migrants, his administration separated families, keeping the children in the United States for resettlement while shipping the parents back over the border, with no contact.
Unaccompanied children were detained for months, some even lost in the system.
Now, in Brownsville, it's a smooth process that local activists say is more humane.
Around 150 migrants who landed as families pass through every day. After registering with CBP, they get dropped off at the bus station or the airport.
Mayor Trey Mendez said Monday that they are treated like guests and usually leave for their destinations within 24 hours.
At the station, volunteers from Team Brownsville, an NGO, give them clothes and toys for the children.
A nearby homeless shelter, Good Neighbor Settlement House, sends over boxed meals and kits of toiletries.
And another group, funded by donations, gives each migrant a Covid-19 test. So far, said Mendez, 7.3 percent have tested positive.
"The rate is less than our community rate; it's less than the state average," he said.
The migrants all have relatives somewhere across the United States -- a husband in Virginia, an uncle in Indiana, or cousins much closer in Houston.
Several that AFP spoke to said that Biden's more open policy encouraged their journey.
One said her husband, already inside the United States, said it would be easier and safer under Biden.
But all also say they are fleeing the lack of jobs and money, and constant threat of violence -- "delinquents and narcotraffickers who nobody messes with," said Carillo-Ramos.
Sam Bishop, who works with Global Response Management, which provides medical support for migrants in Matamoros, said they sound like the refugees fleeing violence that he dealt with as a US military medic in the Middle East.
"Many of the people there in Syria, who are recognized refugees fleeing violence by ISIS, have stories that would be interchangeable with the stories of people that we see here," he said.
Defending the government's policy, Biden pointed to earlier surges, including in 2019.
He spoke hours after his of Homeland Security Alejandro Mayorkas admitted what previous administrations have all found: that "The situation at the southwest border is difficult."
Mayorkas blamed Trump's harsh and haphazard stance approach for the current problems.
"We are on pace to encounter more individuals on the southwest border than we have in the last 20 years," he said.
And while he claimed that most migrants from Central America were being expelled, he admitted that in areas like Brownsville, the families were being let through -- acknowledging that Mexico doesn't want to take them back.
"I came to this country as an infant, brought by parents who understood the hope and promise of America," said Cuba-born Mayorkas.
"Today, young children are arriving at our border with that same hope. We can do this."