CNN  — 

White House deputy chief of staff Stephen Miller told reporters Friday that the Trump administration is “actively looking at” suspending habeas corpus — a legal procedure that allows people to challenge a government’s decision to detain them.

“The privilege of the writ of habeas corpus can be suspended in a time of invasion,” Miller told reporters Friday. “So it’s an option we’re actively looking at. Look, a lot of it depends on whether the courts do the right thing or not.”

Suspending habeas corpus would require, under the Constitution, that the country be “in Cases of Rebellion or Invasion the public Safety may require it.”

While it’s unclear whether the idea of suspending habeas corpus is under serious discussion within the West Wing, Miller’s comments pick up on ongoing efforts by the Trump administration to use the current state of illegal border-crossings to claim that there is an invasion — which the administration says allows the government to eschew due process protections afforded to migrants. The administration is making a similar argument in defending Trump’s invocation of the Aliens Enemies Act, which would allow the government to quickly deport migrants without adherence to such due process procedures.

Multiple judges, including a Trump appointee, have rejected the invocation, saying in rulings that the administration hadn’t shown the United States is under invasion by a hostile foreign power, as laid out under the 18th century statute.

Suspending the writ of habeas corpus would take Trump’s efforts even farther — allowing the government to detain migrants without giving them the opportunity to challenge that detention, essentially allowing the administration to detain people without providing justification.

“The writ of habeas corpus has been suspended a number of times, but only in times of actual war or actual invasion, narrowly defined,” Ilya Somin, a professor of law at George Mason University, told CNN in January.

While the Constitution does not explicitly require Congress’ approval for such a suspension, it’s long been understood that the legislature would likely need to play that role, as the late conservative Justice Antonin Scalia has noted in a dissent.

Somin said some states have also tried to claim, starting in the 1990s, that illegal immigration amounted to an invasion that would allow them to engage in war or to disregard federal laws that restrict immigration enforcement.

“Every time courts have ruled on this, they have ruled against the states,” Somin said.

Trump administration officials have made it clear that they believe the judicial branch is hindering their ability to enforce immigration laws. President Donald Trump has personally attacked judges in public statements, and Miller has likened court rulings against the administration to a “judicial coup.”

In a sign of the mounting pressure, Chief Justice John Roberts stressed the importance of judicial independence during public remarks Wednesday.

“The judiciary is a coequal branch of government, separate from the others with the authority to interpret the Constitution as law and strike down, obviously, acts of Congress or acts of the president,” Roberts said at an event in his native Buffalo, New York.

The judiciary’s role, Roberts added, is to “decide cases but, in the course of that, check the excesses of Congress or the executive.”