This article is republished from The Conversation, an independent and nonprofit source of news, analysis and commentary from academic experts. Rose Cuison-Villazor is a Professor of Law and Chancellor's Social Justice Scholar; Director, Center for Immigrant Justice, Rutgers University - Newark
News reports of noncitizens unexpectedly being detained by , or ICE, have dominated headlines in recent weeks. Those being detained include noncitizens who hold lawful permanent residency status.
One story concerns the March 8, 2025, , a lawful permanent resident and recent Columbia University graduate, who was initially detained in New Jersey and transported to Louisiana. He remains there while he challenges his detention and the immigration
And on March 25, , a Turkish national and doctoral student at Tufts University, while she was walking on the streets of Somerville, Massachusetts. She is in Louisiana.
ICE agents have also detained and removed, among other people, hundreds of Venezuelan noncitizens to El Salvador since March, legal cases that are making their way through the court system. And the U.S. has revoked the visas of at least this year.
As , I think that it is important to help the public understand the scope and limitations of ICE鈥檚 authority.
At the most basic level, ICE has broad, sweeping powers to question, arrest, detain and process the . But ICE is still bound by certain constitutional and other legal restrictions, including noncitizens鈥� rights to make their case in court to remain in the U.S.
ICE鈥檚 mission and work
Created as part of the in 2003, ICE is one of the responsible for enforcing immigration laws.
ICE鈥檚 operating budget from Oct. 1, 2024 through Sept. 30, 2025 is approximately US, a relatively small portion of Homeland Security鈥檚 total budget for that same time period.
With more than 20,000 immigration enforcement officers stationed across the country, ICE鈥檚 day-to-day work is divided into 鈥� homeland security investigations, enforcement and removal operations, and legal representation for the government in an immigration court.
The branch focused on homeland security investigations probes transnational crime and terrorism-related activities. ICE鈥檚 second area of work focuses on apprehending and removing noncitizens who are in violation of immigration laws. Finally, staff at the Office of the Principal Legal Advisor in immigration hearings, particularly what is called removal proceedings, .
is primarily granted through the , in 1952 amid the Cold War.
This act outlines the federal government鈥檚 authority to regulate immigration and provides immigration agencies, including those established at a later date, like ICE, broad powers to enforce these restrictions. One key allows ICE officers to interrogate any individual they believe to be a noncitizen regarding .
The Immigration and Nationality Act also can be deported for engaging in activities that the secretary of state believes 鈥渨ould have potentially serious adverse foreign policy consequences for the United States.鈥�
Secretary of State Marco Rubio when he . Ozturk was in March 2024 calling for Tufts University to recognize genocide against the Palestinian people.
Rubio used the same provision to claim that Khalil鈥檚 involvement in protests at Columbia University had negative U.S. .
Detain and arrest
ICE officers have broad power to arrest noncitizens in the U.S.
With a warrant, they may arrest noncitizens who are , including foreign students whose visas . These warrants are administrative warrants signed by an immigration enforcement supervisor 鈥� .
ICE officers have long been able to carry out these arrests in plain clothes 鈥� although using face coverings, as ICE officers who arrested Ozturk and Khalil did, .
Still, ICE鈥檚 powers to interrogate, arrest and detain noncitizens are not absolute.
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For one, immigration law requires noncitizens to be notified in writing that they are being processed for a removal proceeding, so they can appear before an immigration judge and have the opportunity to .
Noncitizens have the right to legal representation 鈥� albeit not paid for by the U.S. government 鈥� in an immigration court. Ultimately, an immigration judge, and not ICE, determines if a noncitizen should be deported.
The Constitutional limits on ICE
Crucially, ICE is bound by various constitutional provisions that protect individual rights, including the rights of noncitizens who are living in the U.S. without legal authorization.
Three particular constitutional amendments impose different checks on ICE鈥檚 power.
, for example, protects individuals鈥� rights to free speech, assembly and religion. Consequently, ICE cannot target individuals 鈥� even if they are noncitizens living in the U.S. without legal permission 鈥� for simply participating in peaceful protests or writing something for the public. that he revoked Ozturk鈥檚 visa not because of her writing, but because she participated in 鈥渁ctivities that are counter to our foreign 鈥� policy.鈥� He also relied on this provision to support the deportation of Khalil.
But Ozturk and Khalil鈥檚 lawyers contend that their activities were protected speech. Ultimately, a federal district judge has the power to determine whether ICE targeted them for exercising their First Amendment rights.
safeguards the right of individuals 鈥渢o be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures.鈥� ICE must first obtain a search warrant, signed by a judge, before entering a person鈥檚 home or private areas of a workplace.
The against unreasonable searches and seizures also applies in public spaces. So, law enforcement officers must have reasonable suspicion to stop a person 鈥� or have probable cause to not have a warrant when they arrest a person they believe is guilty of a crime or in violation of a law and likely to escape. The Immigration and Nationality Act also requires ICE officers to have an arrest warrant unless they have reason to believe that the before they get a warrant.
It is not clear whether ICE officers presented Khalil and Ozturk with arrest warrants before they were detained outside their home and on the street, respectively.
guarantees the right of all individuals against self-incrimination. This means that people detained by ICE have the right to remain silent during interrogations.
It also means that before noncitizens can be deported, they must have the opportunity to go before an immigration judge to challenge the government鈥檚 plan to remove them, or may file a case before a federal judge to challenge their detention and deportation.
ICE鈥檚 power is not absolute
Even with an annual budget of , ICE does not have the capacity to pursue all immigration law violations.
In this context, recent Trump administration initiatives could significantly increase ICE鈥檚 reach. For example, of understanding between the Internal Revenue Service and DHS allows the IRS to living in the U.S. without legal authorization. This could help ICE more easily identify, locate and arrest noncitizens living in the U.S. illegally.
Despite its considerable power, ICE鈥檚 authority is not without checks and balances.
But as a longtime scholar of immigration law, I believe ICE officers鈥� recent actions raise serious concerns that it is exceeding the bounds of its legal authority and the constitutional limits that are intended to protect individual rights.
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