Can Green Card Holders and Student Visa Holders Be Deported?

The arrest of a Palestinian activist who helped organize protests on the Columbia University campus against the war in Gaza has raised questions about whether foreign students and green card holders are protected from deportation in the U.S.
Can green card holders be deported?
The green card holder has legal permanent resident status in the United States.
Jaclyn Kelley-Widmer, a law professor at Cornell Law School specializing in immigration law, stated that legal permanent residents generally have many protections. But this protection is not absolute. Green card holders can still be deported for committing certain crimes, failing to notify immigration officials of a change of address, or engaging in marriage fraud, for example.
Other experts say that the federal government has quite broad authority to detain and attempt to deport a green card holder based on allegations of terrorism, as in the case of the arrested activist Mahmoud Khalil. The government accuses former student Mahmoud Khalil, who was a green card holder, of involvement with the terrorist group Hamas, which has not been proven by any evidence.
Under the Immigration and Nationality Act, green card holders do not need to be convicted of anything to be considered “removable,” Kelley-Widmer said. They can be deported if the Secretary of Homeland Security or the Attorney General has reasonable grounds to believe they have engaged, or are likely to engage, in terrorist activities, she states.
But Kelley-Widmer said she has never seen a case where the alleged terrorist activity occurred in the U.S., and questioned whether participating in protests, as Khalil did, qualifies.
Student visa is another story
When it comes to someone who is a legal permanent resident, generally an immigration judge needs to determine whether they can be deported.
In the case of a student visa, the U.S. Department of State can cancel it without needing a judge and for less serious reasons. For example, it is quite common for the Department of State to cancel foreign student visas for those arrested for driving under the influence.
If someone is in the country on a student visa, the Department of State does have the authority to revoke it if the person violates certain conditions.
Sources: PBS News