From the early days of state-based immigration policies to the explicitly racist Chinese exclusion laws of the 19th century, the systematic deportations of Mexican Americans in the mid-20th century to the hypercriminalization of immigration policy in recent decades, the United States has long been preoccupied with who can be included in our national story, who should be expelled from it, and what muscles the federal government should flex to achieve each goal.

But after 100 days of Donald Trump’s second term in office — a few short weeks marked by an increasingly aggressive authoritarian power grab and the racist dehumanization of migrants — even some experienced academics are struggling to express what has happened.

“The cruelty with which they’re pursuing expulsion of immigrants is shocking even to me,” said Mae Ngai, an acclaimed historian at Columbia University who’s spent decades studying the origins of America’s immigration enforcement regime, including the creation of the concept of “illegal aliens” itself.

“The principle of checks and balances ... that idea seems to have been thrown out the window,” said Emily Ryo, a scholar of immigration enforcement and the legal system at Duke Law School. She described what she saw as the administration’s embrace of “this view of unfettered executive power that appears to be crossing over onto more blatant disregard for the existing legal system that’s in place — in rolling defiance of court rulings and court orders.”

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“We may see a future where Trump decides to back down, so as not to burn the Constitution,” said Jeremy Slack, chair of the sociology and anthropology department at the University of Texas, El Paso, who’s spent years surveying migrants at the U.S.-Mexico border about their experiences. “I’m not super optimistic about that.”

In conversations with HuffPost this month, scholars of immigration history and enforcement in the United States — historians, sociologists, legal theorists — rang alarm bells over what many described as generational abuses of power by Trump.

They made clear that the tools at Trump’s disposal — dehumanization, surveillance, detention, expulsion — have long been a part of presidents’ arsenals. But they also distinguished what has made these past 100 days so extraordinary: Trump’s aggressive seizure of power, and his disregard for anything that might restrain him.

“It’s important to understand that we’ve never had a president who uses power, and instruments of power, in this way,” said Benny Andrés, a professor of history at the University of North Carolina at Charlotte who last year co-edited a special issue of the journal California History marking Border Patrol’s 100th anniversary.

“No one has flaunted the traditions or authority like he has. He is purposefully stressing the system.”

‘Anybody Is At Risk’

More than any specific policy, Trump’s “mass deportation” agenda is stressing the very foundations of America’s constitutional system.

Trump has sent at least 288 people who’d previously been living in the United States — mostly Venezuelans, some Salvadorans — to El Salvador’s brutal Centro de Confinamiento del Terrorismo, or CECOT, despite several federal judges explicitly ordering otherwise. Thousands more could follow, and the administration has similarly used Guantánamo Bay to house migrants, echoing past uses by presidents of both parties.

CECOT is known for brutal conditions and unconditional life sentences. But none of the men sent there by the United States are being detained as the result of any actual conviction in a court of law. Several attorneys and legal scholars have told HuffPost the detainee transfers meet the definition of “enforced disappearances” — where there’s been no official acknowledgement by the Trump administration of who has been sent to CECOT, despite there being no trace of the men left in the United States.

The men were hustled to the prison under a rarely used wartime power, the Alien Enemies Act, or after they’d received standard deportation orders from a judge. The Trump administration has argued — almost entirely without any evidence, let alone criminal charges — that the men are gangsters. On this say-so alone, they’ve disappeared to a foreign black site, perhaps forever.

Even after the Supreme Court told the administration that a lower court was right to tell him to facilitate the return of one man in that group who’d had a protection against being deported to El Salvador specifically, Kilmar Abrego Garcia, the administration has taken no action to bring him back.

Alongside its use of CECOT, the administration has targeted visa holders and permanent residents who’ve called the United States home for years, seemingly only due to the nature of their political opinions. Often, these arrests are carried out with no warning, using masked agents who quickly whisk their subjects several states away, depriving them of ready access to their lawyers. (For many, this recalls the so-called Palmer Raids, when the federal government arrested thousands of Communists, anarchists, labor union members and others, and deported hundreds of them.) Thousands of student visa holders are said to have been impacted by Trump administration records purges, which threw their legal status in question. The administration has said it’s paused those purges — for now.

Trump has also sought to end birthright citizenship, the longstanding constitutional right that anyone born in America — with rare exceptions like the children of foreign diplomats — is a citizen here. In Trump’s reading, this also excludes the children born in the United States to temporary visa holders.

“The piece that really jumps out to me is this idea that the law, and the actual legality of your [immigration] status does not matter,” Slack said. He pointed out that Vice President JD Vance has called people “illegal” who are in fact here legally, and that the Trump administration has referred to anyone here in violation of immigration law — often only a civil offense, not a criminal one — as a criminal. The administration has even targeted people with open asylum cases, which under U.S. law entitle them to their day in court.

“You combine those two pieces, and it’s basically giving a carte blanche to say, ‘any immigrant is subject to anything we want at any time,’” he said. “The prima facie assertion that somebody is illegal whenever we want, that’s where it gets really scary, because it means that every immigrant is under threat.”

Then there’s the matter of the administration expelling U.S. citizens from the country. In three recent cases, the administration sent small children — one of them a 4-year-old cancer patient — to Honduras along with their mothers despite the children being U.S. citizens.

Historians have estimated that hundreds of thousands of U.S. citizens, mostly of Mexican descent, were similarly sent out of the country during the 20th century.

Throughout history, “we as a country are weirdly comfortable with that sort of functional removal of U.S. citizens, but this looks different,” said Jennifer Chacón, a professor at Stanford Law School who focuses on immigration law, constitutional law and criminal law and procedure.

“If you know this is a citizen, and you know you shouldn’t be willy-nilly removing citizens, it seems like you then take the time to figure out if there is in fact a family member in the United States with whom the citizen child can remain.”

Chacón argued that the lack of due process rights for people facing expulsion from the country, combined with the lack of investigation or accountability over “mistakes” made by immigration agents, is a dangerous combination.

“If there’s no cost for error, and there’s no procedural protection, then it seems to me that anybody is at risk, particularly people who are vocally critical, particularly people who are a thorn in the side, particularly people who fit phenotypically or descriptively into categories that the administration has labeled ‘dangerous’ and ’poisonous to the blood,’” she said.

Alongside the administration’s attacks on individual legal rights, it’s also gone after the legal process itself, attacking legal aid funding for unaccompanied migrant children, singling out immigration attorneys in an executive order, and pursuing a retribution campaign to target several large law firms whose employees often take on immigration cases pro bono.

A key official has threatened a member of Congress with criminal prosecution for merely holding “know-your-rights” workshops. FBI agents recently arrested a state judge over thin allegations she helped an undocumented man evade arrest.

“[Between] trying to block federal funding from sanctuary jurisdictions, and now trying to go after lawyers who are suing them, they’re really trying to shut down the points of resistance that worked in the first Trump administration,” said Margot Moinester, a professor of sociology at Washington University in St. Louis who focuses on U.S. immigration enforcement.

Referring to attacks on the legal profession, Ryo, of Duke, said she was “already seeing what kind of trickle-down effect that’s having, because we’re already seeing law firms pull back on that type of [immigration] work that they have been doing, due to fear of retaliation.”

For Andrés, the most notable part of the administration’s enforcement agenda has been the near-silence of its co-equal branch: Congress. Other significant enforcement shifts in U.S. history have come through legislation, he said; 1920s legislation was “discussed, debated, reported” publicly for years. Now, he says, Congress is “not functioning,” and has not provided any meaningful check against Trump. Chacón similarly described a “totally dysfunctional, non-functioning, non-entity legislative branch.”

“This is, to me, the most dangerous, the most alarming outcome of the last three months,” Andrés said.

The Control Boom

To understand Trump’s immigration enforcement agenda, it’s crucial to understand U.S. immigration history. For decades, politicians of both parties have built up the government’s ability to detain and deport people on a massive scale, setting the stage for Trump to push the envelope even further.

The federal government was largely uninvolved in immigration enforcement for the country’s first 100 years. In the late 19th century, responding to a generation of Chinese immigrants and the nativist reaction that followed, Congress passed a slew of laws meant to exclude Chinese people. The 1924 Johnson-Reed Act, passed during the height of the eugenics movement, later set quotas for immigrants of each nationality based on the 1890 census, disproportionately impacting southern and eastern Europeans. The 1965 Immigration and Nationality Act redefined immigration qualifications, replacing national quotas with family- and skills-based criteria.

In 1996, President Bill Clinton signed the law that arguably shaped our current situation more than any other — the Illegal Immigration Reform and Immigrant Responsibility Act, or IIRIRA. “Ira Ira,” as it’s called, expanded the grounds on which longstanding U.S. residents could be deported, and made it much harder for people to “legalize” their U.S. presence. Deportations spiked dramatically.

The most recent immigration enforcement legislation to become law is the Laken Riley Act, which adds even more grounds for the mandatory detention of undocumented people. Now, even someone simply accused of shoplifting must be detained. The bill received the votes of 12 Senate Democrats in former President Joe Biden’s final days, and was signed into law a week into Trump’s second term.

“The No. 1 thing that’s been driving deportations [in recent history] is the expansion of who lives in the United States who’s vulnerable to it, and also, how the federal government has expanded its capacity to find and apprehend people,” said Moinester, who has written about a “control boom” – the process of American immigration enforcement growing more punitive, expanding “the specter of deportability and, in turn, social control.”

As the rules changed, so did their enforcers. Initially, immigration matters were handled by the states, then the Treasury Department and then the Department of Labor. Eventually, the Justice Department took over. After Sept. 11, 2001, immigration enforcement was consolidated in the Department of Homeland Security, and funding went up massively, as did the use of for-profit prisons. What was once a local economic and labor concern had now “come to be seen as a matter of national defense,” said Jonathan Cortez, a professor of history at the University of Texas at Austin.

In the early 20th century, “the United States, for the most part, saw immigration as an act of good faith — as an act of coming to the United States mostly for economic promise,” Cortez said. As the decades progressed, “policies against immigrants became harsher”

Trump’s immediate predecessors played key roles expanding what some call the U.S. “deportation machine.” President Barack Obama still holds the single-term record for most interior deportations in modern U.S. history, which he achieved largely through extensive cooperation with local police departments. (Opposition to that record gave rise to the modern swell in so-called “sanctuary cities,” where local policy restricts cooperation with immigration agents.)

Biden, for his part, set onerous new restrictions on pursuing asylum at the southern border, which did dramatically cut down on unauthorized border crossings — but also provided legal precedent for Trump’s even-more-extreme crackdown on asylum.

Notably, a recent DHS memo explained that immigration agents would not affirmatively ask people whether they were afraid of being deported to a given “third country,” or a country other than that of their original citizenship. Critics have said this practice, which also occurred during the Biden administration, means that migrants who are unaware of their ability to express a fear of being deported could be deported to dangerous situations.

The Trump policy cited a June 2024 regulation – one that was issued pursuant to Biden’s asylum crackdown.

What Trump Inherited

Trump’s second term expands on the inheritance he’s received from past presidents and legislators.

For example, Trump has demanded that every undocumented person in the country register with the government, information that will almost certainly be used to target people for deportation, while threatening criminal charges against those who don’t sign up. It may be a Trumpian ploy to pursue criminal charges against vast numbers of people, but it also relies on a seldom-used portion of the Immigration and Nationality Act of 1952. (President Harry Truman vetoed that legislation, but Congress overrode him with a two-thirds majority.)

Trump’s effort to further deputize local law enforcement to do ICE’s bidding is part of what’s known as the 287(g) program, which was signed into law by Bill Clinton, in 1996’s IIRIRA. And Trump’s “border czar” Tom Homan is an Obama administration alumni.

Trump has also exploited existing weaknesses in protections against deportation for migrants.

In particular, the Biden administration offered temporary parole protections for hundreds of thousands of people who sought to come into the country legally — protections Trump is now working to strip away.

For example, the Biden administration used a phone app, CBP One, to allow migrants to schedule appointments at ports of entry and enter the United States under a temporary parole program. Biden also offered temporary parole for migrants from Cuba, Haiti, Nicaragua and Venezuela — “CHNV,” as the program is short-handed — if they arranged for their own travel, arranged for a U.S. sponsor and passed background checks.

Trump has sought to reverse both programs, though like many other initiatives he’s faced court battles. He eliminated CBP One on his first day — anyone with the app still on their phone will find that it was transformed last month into a platform to schedule “self-deportation.”

More broadly, Trump began his second term with a flood of executive actions, all but shutting down the U.S. refugee program — except, eventually, for white South Africans — and reversing Biden-era guidelines that prioritized immigration enforcement against people deemed public safety threats. On top of his attacks on parole recipients, Trump has also gone after thousands of Venezuelans, Haitians and Afghans who’ve received “temporary protected status,” which covers countries with extreme political or environmental instability.

And he’s pulled scores of federal agents — from the IRS, DEA, even State Department diplomatic special agents — off of other jobs and onto immigration enforcement, empowering them to enter schools and churches to make arrests. And, like in his first term, he’s pushed to use so-called “expedited removal” to quickly deport people who’ve been in the country for any less than two years, without a hearing — rather than the old standard of 14 days.

In Trump’s first 100 days, he’s stuffed U.S. immigration jails full. As of earlier this month, nearly 48,000 people were in ICE detention, a six-year high, according to the Transactional Records Access Clearinghouse.

‘Chilling’ Propaganda

Many of these moves recall Trump’s first term, which also included a policy of systematically separating children from their parents at the border, and a U.S. travel ban for people from several Muslim-majority countries. (A similar travel ban policy is in the works again.)

And there’s no doubt that Trump came to power on Jan. 20, 2025, with a mandate from voters to focus on immigration. Trump ran on a “mass deportation” platform inspired by a similar program during President Dwight D. Eisenhower’s tenure, which was named after a slur and marked by blatant cruelty and violations of rights. And Trump won, securing not only the Electoral College, but also the plurality of the popular vote.

But this is another point that concerns historians. Trump’s mandate is based on the persistent, racist dehumanization of immigrants, who he said were “poisoning the blood” of the nation with “bad genes” and diseases. In an effort to deprive immigrants of public benefits, he’s even literally dehumanized them — digitally “killing” them off of Social Security rolls, even though immigrants without status still pay taxes.

Like prior anti-immigrant movements, Trump has blamed migrants for the economic displacement of U.S. workers affected by broader market forces, Ngai said.

“It’s very frightening and sad that you have some section of the population who likes this, and like Trump because he’s extreme, outrageous,” she said, likening images of CECOT detainees having their heads shaved after being sent there by the United States to Nazi propaganda.

“It’s totally chilling.”

On Monday night, Trump showed some of the CECOT imagery at a rally, as thousands of his supporters cheered on.

What is there to do in the face of a racist, authoritarian government seemingly dead set on pursuing “mass deportation” without protecting the legal rights of its residents, regardless of their legal status? Ngai and others said history showed a way forward.

“I do believe that any time we’ve had reform in immigration policy, it’s because the immigrants themselves, and their communities, are organized,” she said, noting the success of activists to achieve immigration reform in the 1960s. “We shouldn’t discount the organizing capacity of immigrant communities.”

Chacón, of Stanford Law School, said that given the administration’s apparent disregard for the courts, public pressure was crucial.

“I think they’ve already indicated that it is not the law that holds them, it is the public response that holds them accountable,” she said. “I guess I’m already past the point where I’m wondering, ’Is the administration going to comply with the law or not?’”

Instead, she said, it appears that “this is an administration that will respond to public pressure, and maybe won’t respond to much else.”