Explained | The GOP plan: What it would take to deport millions of immigrants

When Donald Trump ran for president in 2016, he vowed to build a wall to seal the border and keep criminals from entering the country. This campaign season, his immigration agenda has a new focus: a mass deportation program unlike anything the country has seen.

His party's platform, ratified at the Republican convention in Milwaukee, promises the "largest deportation effort in American history," and immigration was the theme of Tuesday's gathering.

What would it take to deport millions of people? Is it even possible?

How many immigrants are in the country illegally?

There were 11 million immigrants living in the United States without legal permission in 2022, according to the latest government estimates, and more than 8 of 10 have been in the country for more than a decade. Trump said during the debate last month that there were 18 million, which is unsubstantiated.

Fleeing political and economic turmoil, migrants from countries like Venezuela have crossed the border in record numbers during the Biden administration.

Who would be targeted for deportation, and how easy would it be to remove them?

Trump and the Republican platform have made broad declarations but thus far offered scant details about their intended operation.

The former president has suggested that any immigrant lacking legal status is subject to removal.

The party platform states that "the most dangerous criminals" would be prioritized.

It also said: "The Republican Party is committed to sending illegal aliens back home and removing those who have violated our laws."

The consensus among immigration experts and former homeland security officials is that logistical, legal, bureaucratic and cost barriers would make it virtually impossible to carry out the mass deportations Trump seeks in the span of a four-year presidential term.

"It's enormously complicated and an expensive thing to decide to deport people who have been here years," said Laura Collins, an immigration expert at the George W Bush Institute in Dallas.

It would cost "billions of dollars. It would probably take 20 years. It would cause the economy to shrink," she said.

It would require an enormous influx of resources throughout the enforcement system and billions in new appropriations.

"Even if he had a Congress willing to enact dramatic statutory reforms and appropriate the tens of billions required, there is no way such a system could be fully functional within a four-year period," said John Sandweg, a homeland security official in the Obama administration.

What other obstacles would there be?

Immigrants who have lived in the country for years have legal protection and the right to due process.

Those who have entered the country unlawfully in recent years have been processed at the border and then released with orders to appear in court for deportation hearings. While their cases are winding through the immigration court, which typically takes several more years, they have the right to remain in the United States.

"Trump would need to triple the size of the immigration court to achieve anywhere near the numbers he is talking about," said Sandweg. "Even then, he would need funding to build new courthouses, hire support staff and train judges."

Decades of underfunding and a vast number of asylum claims have exacerbated backlogs.

"An individual must be issued a deportation order; a president couldn't just override that," said Janet Napolitano, Homeland Security secretary during the Obama administration. "You would need a change in the law, and Congress would have to be an active partner in this."

In addition to the cost, a polarized Congress, even one controlled by Republicans, would still have to reach a consensus on the substance of the operation, a daunting prospect considering Congress has failed to overhaul the immigration system for more than two decades.

Are there enough personnel, facilities, planes and other transport for a deportation operation?

During the Trump administration, there were some 936,000 deportations, according to official data. As of February, about 340,000 people had been removed by the Biden administration.

To identify and arrest millions of people in the interior of the country would require tens of thousands more immigration agents, said Napolitano.

Trump has said he would enlist the National Guard and other resources in the military to execute his plan.

Local law enforcement could be deputized to identify people without legal status and turn them over to Immigration and Customs Enforcement, which has happened in the past in some localities.

But Chicago, Denver, Los Angeles and Philadelphia are just a few cities that refuse to collaborate with ICE, out of concern such cooperation would promote racial profiling and land immigrants who have committed minor offenses, such as traffic violations, in deportation proceedings.

"You'll have areas that don't want to have anything to do with it," said Michael Neifach, a border security expert who was principal legal adviser to Immigration and Customs Enforcement during the George W. Bush administration.

Currently, ICE agents focus on locating and deporting convicted criminals, such as child molesters and others suspected of being a threat to public or national security.

Some 1 million immigrants with final removal orders living in the country could be a targeted group.

"Let's say you find these people. You then have to detain them," said Neifach. "How are you going to expand detention in a way that won't blow the bank?"

Every potential deportee is held in a detention facility, and in the current fiscal year, Congress funded the detention of 41,500 immigrants daily at a cost of $3.4 billion (Rs 28,437 crore), which would need to increase exponentially.

And many immigrants hail from countries that do not have diplomatic ties with the United States or that refuse to take back their nationals. They cannot be immediately flown out of the country, and the Supreme Court has ruled that people cannot remain detained for limitless periods awaiting removal.

The ICE budget for transportation and deportation in fiscal 2023 was $420 million (Rs 3,512 crore), and the agency deported 142,580 people that year.

Where is there room for Trump to accelerate the pace of removals?

Another Trump administration could speed up deportations by terminating programs that the Biden administration has introduced.

For example, since 2022, some 500,000 people from Cuba, Haiti, Nicaragua and Venezuela have been allowed to fly to the United States and live and work for two years, provided they have a financial sponsor. Biden has also allowed nearly 700,000 migrants who make an appointment on a mobile app to cross the border through an official port of entry and receive work permits.

"Trump could flick the switch and revoke it," said Neifach. But, he added, many of the migrants could make asylum claims and become part of the clogged courts.

Expedited removal at the border enables the swift deportation of migrants without a hearing, unless they convince an agent that they would face the threat of violence back home, and Biden in June issued an executive order currently being challenged in court to amplify use of this tool.

Trump could try to extend it to the interior, though he would likely face court challenges.

Would there be any exceptions among the deportees?

Trump has not addressed whether he would exercise any discretion, or make any exceptions.

More than 1 million Americans are married to a person without legal status, and a large share of immigrants have children who are US citizens.

"When you are talking those kinds of numbers and law enforcement presence, you have to think at the end -- what does that do to the atmosphere in the country?" said Napolitano, the former Homeland Security secretary.