(WHTM) — The Trump administration has announced they are “actively looking at” suspending habeas corpus. Here’s what that means.

According to the Cornell University School of Law, habeas corpus is Latin for “that you have the body.” Cornell says in the United States, federal courts can use habeas corpus to determine if a state’s prisoner detention is valid. The writ, or order, of habeas corpus is used to “bring a prisoner or other detainee (such as an institutionalized mental patient or illegal immigrant) before the court to determine if the person’s imprisonment or detention is lawful.”

Cornell University says the sources of habeas corpus are the Constitution, statutory law, and case law. The Constitution does not specifically create the right to habeas corpus relief, but federal statutes do provide federal courts with the authority to grant habeas relief to state prisoners, per Cornell.

According to Cornell, only Congress can suspend habeas corpus. The president can delegate the suspension to Congress, but the Executive does not have the independent authority to suspend the writ.

Article I, Section 9 of the United States Constitution says, “The Privilege of the Writ of Habeas Corpus shall not be suspended, unless when in Cases of Rebellion or Invasion the public Safety may require it.”

Whether the United States is in a ‘rebellion’ or ‘invasion’ is up to interpretation; however, federal courts have historically ruled that illegal immigration does not constitute invasion. A top aide of the Trump administration told BBC News that they are “actively looking at” suspending habeas corpus.