President Donald Trump directed U.S. government agencies to no longer issue citizenship documentation to babies born in the United States to parents who lack legal status, one of several immigration-related orders he signed in the Oval Office on Monday evening after his inauguration.

Trump’s order seeks to reinterpret the 14th Amendment of the Constitution, which grants citizenship to all people born on U.S. soil, a change legal scholars say is illegal and will be quickly challenged in the courts. The birthright order was part of a burst of immigration-related directives aimed at undoing Biden administration policies and wielding obscure presidential powers to launch a broad crackdown along the border and across immigrant communities.

Trump said during his inaugural speech that he will invoke the Alien Enemies Act of 1798, a wartime authority, to deploy the “full and immense power of federal and state law enforcement” to eradicate foreign gangs and criminals from the United States. The act has been deployed only three times during conflicts, most recently during World War II, when U.S. officials forced 120,000 Japanese Americans and others to live in prison camps.

“I have no higher responsibility than to defend our country from threats and invasions,” Trump said. “We will do it at a level that nobody has ever seen before.”

He declared a national emergency at the southern border to restart border wall construction and direct the armed forces to provide troops, detention space, transportation, including aircraft, and other services to boost border security.

“All illegal entry will be halted,” he said.

Asylum seekers who made appointments to come to the U.S. border Monday afternoon were blocked at international crossings after Trump officials halted use of the CBP One mobile app, which the Biden administration used as a scheduling tool. Trump also ended all “categorical” parole programs that under President Joe Biden allowed 30,000 migrants per month to enter the country via U.S. airports, bypassing the border, for applicants from Cuba, Venezuela, Haiti and Nicaragua.

Lawmakers gave Trump’s agenda an additional boost Monday evening as a dozen Democratic senators joined Republicans to approve the Laken Riley Act. The bill, named for a Georgia nursing student whose murder by a Venezuelan migrant last year became a cause célèbre for Trump’s campaign, will require U.S. authorities to jail immigrants accused of minor property crimes such as shoplifting. The measure is now headed to the House, where it is expected to pass, and it will probably be the first piece of legislation Trump signs into law.

Trump said that the armed forces have “played a long and well-established role in security U.S. borders,” and he directed the defense secretary to deliver a plan within 10 days that assigns U.S. Northern Command, which oversees operations in the North America, to “seal the borders and maintain the sovereignty, territorial integrity, and security of the United States.”

Additional orders directed officials to restart the “Remain in Mexico” policy of Trump’s first term, and to designate drug cartels and gangs as foreign terrorist organizations. Another order suspended refugee admissions — a pause Trump officials said will be in place for four months.

Trump’s rapid-fire decrees have been crafted to immediately put immigration advocates and other opponents on their heels, his aides say. They view his November win as a mandate to order sweeping changes to the U.S. immigration system and said the record influx of unlawful crossings in the first three years of the Biden administration demands bold action.

But lawyers say they have been preparing for months, and many stayed up late Monday night to consider challenges to his orders on birthright citizenship and other issues.

“This is hallmark Trump, doing what he wants, when he wants, how he wants, the U.S. Constitution be damned,” said California Attorney General Rob Bonta (D) in an interview Monday. “That’s not how it works in our democracy.”

Trump officials provided few details Monday about how the new policies would correspond with existing federal law, international treaties and ongoing federal litigation. An official also declined to specify when U.S. troops would be sent to the southern border, how many will be involved and the rules of engagement for possible military activity against foreign drug cartels. The official said those details would be worked out by the secretaries of defense and state.

Attempt to end birthright citizenship

The move to end birthright citizenship fulfills a goal long held by conservative groups that say too many migrants are crossing into the United States illegally to have U.S. citizen children. Trump’s order would stop the State Department from issuing passports and direct the Social Security Administration to no longer recognize the babies as U.S. citizens. The order will take effect in the next 30 days.

It is unclear how many U.S.-born children of undocumented immigrants are in the United States or are born each year. About 4.4 million U.S.-born children under 18 were living with an undocumented parent in 2022, according to the Pew Research Center. At least 1.4 million adults have parents who are undocumented.

In 2018 and 2019, Trump threatened to sign an order revoking birthright citizenship, but he never did. The Congressional Research Service said then that prevailing legal interpretations held that children of undocumented immigrants are citizens. But the service cautioned that the Supreme Court “has not firmly settled the issue in the modern era.”

The Washington Post analyzed more than 4.1 million U.S. immigration court records from the past decade to find out where migrants come from and where they live once they arrive in the country.

Sending troops to the border

Defense Department officials held discussions last week that sought to keep active-duty forces out of any kind of law enforcement role, a cultural and political land mine that senior military officials have long been keen to avoid because of the damage it could do to the U.S. military as an institution. Defense officials will follow legal orders from the new president, according to one Pentagon official, but must adhere to the Posse Comitatus Act, which limits the use of active-duty troops in domestic law enforcement.

During his first administration, Trump sought to invoke the Insurrection Act to use active-duty forces to help quell domestic unrest after the police murder of George Floyd in Minneapolis. Doing so would allow the new Trump administration to use active-duty troops more broadly — and would also immediately be controversial.

Defense officials have typically seen the invocation of the Insurrection Act as a last resort, to be used only when other options are insufficient. The law was last invoked by President George H.W. Bush in 1992 to quell rioting in Los Angeles after the acquittal of police officers who had been recorded beating Rodney King.

Shutting down asylum program at southern border

Although illegal border crossings soared to record levels during Biden’s first three years in office, averaging 2 million per year, his team eventually devised a system of incentives and deterrents to encourage more migrants to seek to enter the United States legally by expanding what it called “lawful pathways.”

Biden officials paired those measures with the harshest crackdown along the border by any Democratic administration in memory. They worked with Mexican authorities to arrest migrants traveling north to the U.S. border, and they issued rules essentially barring access to the U.S. immigration system for anyone who entered illegally.

Those policies produced dramatic results in the final year of Biden’s term. Illegal crossings at the U.S.-Mexico border dropped more than 80 percent in 2024. Over the past few weeks, the number of migrants taken into custody along the border has fallen to roughly 1,000 per day, a level far lower than when Trump left office four years ago.

The latest U.S. Customs and Border Protection data shows more migrants seeking to enter at official border crossings, known as ports of entry, than the number apprehended by Border Patrol after crossing illegally.

Among those seeking lawful entry are the roughly 1,450 people per day who have been using the CBP One mobile app to schedule an appointment to make a humanitarian claim. A notice posted Monday to the agency’s website said future appointments have been canceled. The cancellations will affect about 30,000 people, according to two CBP officials not authorized to discuss the change.

Moments after Trump was sworn in, migrants waiting for their appointments on the border bridge between Ciudad Juárez and El Paso logged on to the app and saw this message: “Existing appointments are no longer valid.”

Increasing deportations

During his speech, Trump said his administration will launch a historic deportation campaign and “begin the process of returning millions and millions of criminal aliens back to the places from which they came.” No government estimates have ever published such a number.

Trump aides said the president’s mass deportation campaign would unfold nationwide, targeting immigrants with criminal records and suspected gang ties. Both categories have long been Immigration and Customs Enforcement’s top priorities, but the officials said Trump’s orders will once more give officers broad discretion to arrest anyone living in the United States illegally.

Trump pledged to immediately deport millions of immigrants when he took office in 2017, but he didn’t come close to that goal. ICE carried out 271,000 deportations during the fiscal year that ended Sept. 30, the highest total in a decade.

Immigration and Customs Enforcement agents gather in Alexandria, Virginia, on October 4, 2022 prepare for a pre-dawn raid. (Tom Brenner for The Washington Post)
The Washington Post examined which groups of immigrants could be at higher risk of deportation under the second Trump administration, and what logistical and financial obstacles stand in the way.

Resuming ‘Remain in Mexico’ program

Trump created Migrant Protection Protocols (MPP), known as “Remain in Mexico,” in January 2019 amid a surge of migrants arriving at the U.S.-Mexico border without permission, crowding border jails and thwarting his promises to limit migration.

The next year, migration plunged amid the global pandemic, though Republican lawmakers have frequently credited MPP for regaining control over the southern border. Biden considered the program inhumane and suspended it on his first day in office, but Republicans fought in court to reinstate it, though their efforts failed once Mexico refused to take people back.

The Department of Homeland Security said the Biden administration had not enrolled any new border-crossers in the program since August 2022, and it gradually admitted those who were awaiting their hearings into the United States.

On Feb. 6, 2023, weeks after a federal judge in Texas ordered the Biden administration to restart MPP, Mexico ended the debate by announcing that it would no longer participate in the program.

“Regarding the possible implementation of this policy for the third time, the Ministry of Foreign Affairs, on behalf of the Government of Mexico, expresses its rejection of the U.S. government’s intention to return individuals processed under the program to Mexico,” the ministry said in a statement.