Why the US expects a border surge and is deploying troops: Explainer

• In preparation for an expected surge of border crossings, the Pentagon is dispatching additional active-duty troops to the US-Mexico border to free up Department of Homeland Security agents.

• Border towns are already bursting with migrants sleeping on the street.

• Big city mayors up north are complaining they are overburdened by migrants already bused from Texas and want action from the federal government.

Migrant surge expected

The surge of migrants is expected because Title 42, the Trump-era policy that allowed the government to quickly turn away certain migrants at the border during the Covid-19 pandemic, is expiring.

It was kept in place by courts and used by the Biden administration.

Title 42 officially ends on May 11, when the Covid-19 public health emergency lapses.

Encounters between US border agents and undocumented immigrants had fallen early this year but have recently increased. They are at around 7,000 per day at the moment and are expected to rise dramatically, despite a warning from the State Department and DHS about a new, more punitive policy related to border crossings.

US troops will not be in a law enforcement role

The additional 1,500 active-duty troops being dispatched for 90 days by the Pentagon will join around 2,500 National Guard troops already on the border. They are meant to act in strictly administrative roles and not to aid in law enforcement, according to CNN's report.

These deployments are not unprecedented in recent years, but this one is notable since it coincides with an expected surge of border encounters.

Biden administration's plan to discourage border crossings

The administration has tried to discourage migrants from simply crossing the border and promised that people apprehended will be turned away and potentially barred from reentry.

The US is working with Colombia and Guatemala to set up regional processing centers to allow migrants to apply to come to the US before they attempt the grueling journey through Central America and Mexico.

"The idea is, of course, that people will not continue their journey over land," a senior administration official told CNN's Priscilla Alvarez recently. "The whole idea of regional processing centers is to give people a lawful, safe, regular way to enter the United States."

But there are already more than 36,000 migrants, according to estimates, camped along the border in northern Mexico waiting for the end of Title 42.

New regulation for asylum-seekers

The State Department and DHS have urged those people to use a mobile app to make an appointment at a port of entry rather than trying to cross the border.

Once Title 42 lapses, the US will return to using what's known as Title 8 authority to remove anyone who arrives at the border unlawfully and bar them from reentering the US for at least five years, a more punitive approach.

A major difference after Title 42 lapses is that asylum-seekers who cross the border without first applying for asylum will be removed under that Title 8 authority, along with a newly proposed regulation, according to the State Department. Immigration advocates are confounded since the Trump administration proposed a similar plan.

The government has pledged to increase the number of refugees allowed into the US and is pushing applicants to use those regional centers rather than travel all the way to the border.

There are also asylum-seekers already inside the US.

On the streets in El Paso

CNN's Rosa Flores recently reported from the streets of El Paso, Texas, where crowds of people had been moved from sleeping on the street to make way for a twice-daily run-through by the city's sanitation services. El Paso has declared a state of emergency in anticipation of the end of Title 42.

Flores said it's mostly men sleeping on the street and that families with children are crowding shelters that have been set up in the city.

Looking for a ride north

From border towns, asylum-seekers hope to get a ride closer to relatives or acquaintances who live in the country.

CNN recently talked to a Haitian family -- 28-year-old Dieuvena, her husband Banel and their 4-year-old son Matéo Sebastien -- struggling to find a place to stay in Boston. After staying in a hospital, the family has had a hard time finding a place to sleep.

Anger from New York's mayor

Texas has been transporting thousands of migrants to cities like New York, Chicago and Washington, DC.

New York City Mayor Eric Adams has asked the federal government to stop giving Federal Emergency Management Agency funds to the Texas border cities using federal dollars to rent buses and ship migrants farther north.

More than 50,000 asylum-seekers have arrived since last spring, according to a separate report by CNN's Alvarez, Mark Morales and Gregory Krieg.

They wrote:

But what was originally seen as a stunt or political provocation -- intended to expose what conservatives describe as hypocrisy among immigrant-friendly Democratic leaders -- has mushroomed into a crisis for Adams, who is desperately seeking federal aid. Advocates' anger over the treatment of the migrants by the city, which initially set up tent camps as shelters, is creating pressure from the left on a mayor who is now threatening budget cuts to everything from libraries to the fire department and Department of Homeless Services.

Targeting certain cities

Adams also accused Texas Gov. Greg Abbott of only sending migrants to cities with Black mayors.

"Governor Abbott sent asylum seekers to NY -- Black mayor; to Washington -- Black mayor; to Houston -- Black mayor; to Los Angeles -- Black mayor; to Denver -- Black mayor. He passed over thousands of cities to land here," Adams said at a recent news conference on an unrelated topic.

"I cannot ignore the fact that Gov. Abbott sent migrants only to cities where there are Black mayors, and it's undermining our cities," he added.

No apologies for buses

Abbott, unapologetic for targeting certain cities that pledged to be immigrant sanctuaries with busloads of migrants, has argued the larger problem is on the border.

The men both want help from the federal government, but they have very different ideas about what that help would look like.

Adams wants the federal government to help deal with asylum-seekers already in the US in a more orderly and fair way. Abbott wants the federal government to repel people at the border.

A haphazard way to make policy

There's a larger point here: Current immigration policy is about to change in a material way not because a reasoned debate led to legislation -- Congress is not seriously debating immigration at the moment -- but rather because the public health emergency is officially ending.

One thing that would help the immigration policy is clarity, according to Ariel Ruiz Soto, an analyst at the Migration Policy Institute.

"Clearly there's significant policy change that is needed at the US-Mexico border; one that actually starts with increasing and providing better assistance for US asylum claims, one that is more fair and transparent about who can come to the country and seek asylum in which ways," he told CNN's Rosemary Church.

There's also very clearly a need for better coordination between the local, state and federal governments about how to treat people already in the US.

It's a great irony of the US political debate that immigration drives such a visceral divide since the country needs immigrants -- both to address labor shortages and to shore up the social safety net programs that are running out of funding.

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