“As President I will immediately end the migrant invasion of America. We will stop all migrant flights, end all illegal entries, terminate the Kamala phone app for smuggling illegals (CBP One App), revoke deportation immunity, suspend refugee resettlement, and return Kamala’s illegal migrants to their home countries (also known as remigration),” Trump wrote in a post to X on Sept. 15.

As President I will immediately end the migrant invasion of America. We will stop all migrant flights, end all illegal entries, terminate the Kamala phone app for smuggling illegals (CBP One App), revoke deportation immunity, suspend refugee resettlement, and return Kamala’s…

— Donald J. Trump (@realDonaldTrump) September 15, 2024

But the campaign promise to get rid of the immigration functions that the Biden administration had added to the U.S. Customs and Border Protection app could trigger an influx of illegal immigrants or have the opposite effect and draw fewer people outside the United States to the southern border, according to immigration policy analysts.

If Trump eliminates the app, immigrants in Mexico would not be able to apply for appointments and choose instead to walk over the border illegally. But turning off the app would also mean immigrants who are in their home countries may choose not to travel to the U.S. knowing that there is no chance of being paroled into the majority through the appointment process.

Doing away with the app could also prompt more people to rush to the border in the short term, hoping to get an appointment on the long wait list, according to Aaron Reichlin-Melnick, senior fellow at the American Immigration Council in Washington.

“Ending the Biden administration’s alternate legal pathways could lead to an increase in migration at the border, although the exact impact is hard to predict with any certainty,” Reichlin-Melnick said in a message. “Ending the CBP One process at ports of entry may encourage some migrants to try their luck crossing illegally instead, rather than wait for months in Mexico for a shot at entering legally.”

The Biden-Harris administration added two functions to the app in early 2023 that allowed immigrants to apply from outside the country for admission or to meet with a U.S. customs officer. The move was intended to give immigrants a way to seek admission without illegally coming over the southern border between ports of entry, but Republicans have criticized it as a backdoor to admit hundreds of thousands of people into the country in less than two years.

The CBP One app permits immigrants from four countries, Cuba, Haiti, Nicaragua, and Venezuela, to apply to enter the U.S. on parole, which allows an individual to remain for two years and receive a work permit. Recipients must have a sponsor in the U.S. and pay for their international commercial flight. Since the process was fully rolled out in January 2023, more than half a million people have been admitted.

The app’s function for allowing immigrants from Cuba, Haiti, Nicaragua, and Venezuela to apply and fly into the country was part of a “carrot and stick deal with Mexico,” and in return, Mexico allowed the U.S. the ability to remove some citizens of those countries at the border back to Mexico.

“Termination of the program could threaten that deal, limiting the ability of the U.S. to address migration from countries like Venezuela which limit deportation flights,” said Reichlin-Melnick.

The app’s second function is to allow immigrants in Mexico to schedule an appointment at a land port of entry on the southern border to meet with U.S. customs officers. Up to 1,450 appointments can be scheduled daily — for a total of more than 43,000 per month. Immigrants who schedule appointments wait months to be seen at one of eight ports of entry used for appointments and are overwhelmingly admitted.

The Center for Immigration Studies takes a hard-line approach on immigration and views the CBP One app as going beyond the executive branch’s authority.

Jessica Vaughan, director of policy studies at Washington-based Center for Immigration Studies, called the CBP One app a “gateway” for immigrants to enter the country because it entices them to travel to Mexico, where they can then request an appointment.

Eric Ruark, research director for nonpartisan immigration organization NumbersUSA, said the Biden White House had yet to reveal if it would increasingly try to increase the number of daily appointments in order to get more people into the country before Trump takes office.

“The Biden administration has used parole and [temporary protected status] and the CBP One app to get people in under what they would say is lawful pathways. Are they going to try to expedite those to get more people in and then have a Trump administration deal with the headache of trying to reverse these things,” said Ruark. “I would anticipate that they’re going to try to expedite getting as many people in before January [2025].”

The Trump administration may already have a solution in place to deal with a potential influx of people who, frustrated appointments are no longer available, choose to come into the U.S. between the ports of entry.

Trump could restart the Migrant Protection Protocols, otherwise known as “Remain in Mexico,” which required immigrants seeking asylum to live south of the border while their cases wound through immigration court.

Additionally, this past June, President Joe Biden took executive action that greatly affected the ability of illegal immigrants arriving at the border to seek asylum and imposed harsh consequences on immigrants who were arrested for illegally crossing the border who did not seek asylum

If Trump kept the Biden executive order in place, immigrants caught between ports of entry “would be automatically disqualified for asylum” and face a five-year ban on seeking asylum.