The Supreme Court on Monday declined to hear the case of a Yemeni citizen detained as an enemy combatant for more than 17 years at the naval base at Guantanamo Bay, Cuba, without being charged with a crime.

The court turned down the petition of Moath Hamza Ahmed al-Alwi without comment. But Justice Stephen G. Breyer said the court may soon need to take such a case to decide whether Congress’s Authorization for Use of Military Force or the Constitution permits indefinite detention.

“Al-Alwi faces the real prospect that he will spend the rest of his life in detention based on his status as an enemy combatant a generation ago, even though today’s conflict may differ substantially from the one Congress anticipated when it passed the AUMF,” Breyer wrote.

The federal authorization was passed in the wake of the attacks of Sept. 11, 2001. Al-Alwi, born and raised in Saudi Arabia, was picked up in northern Afghanistan.

The government says he “received combat training at a Taliban-affiliated camp; stayed at Taliban- and Al Qaeda-affiliated safehouses; was issued a rifle, ammunition, and grenades; and served in a Taliban combat unit in Afghanistan commanded by a high-level Al Qaeda leader until well after September 11, 2001.”

But al-Alwi’s lawyers said lower courts found “no evidence that Mr. al-Alwi ever used arms against the United States or its coalition partners, or that he had anything to do with 9/11 or other attacks on the United States.”

Al-Alwi is among 40 detainees at Guantanamo. “Hundreds of his former fellow prisoners — many facing far worse accusations, some even convicted of war crimes — now live free,” his lawyers told the Supreme Court.

Al-Alwi contended that changed circumstances in the U.S. involvement in Afghanistan meant that he should receive review. The government argued that in recent years, “two presidents have repeatedly reported to Congress that active hostilities ‘remain ongoing’ against Al Qaeda, the Taliban, and their associated forces.”

Breyer did not say that al-Alwi’s case should be granted. But he did say it is “past time” to revisit the issue.

“I would, in an appropriate case, grant certiorari to address whether, in light of the duration and other aspects of the relevant conflict, Congress has authorized and the Constitution permits continued detention,” Breyer wrote.

The case is al-Alwi v. Trump. Justice Brett M. Kavanaugh recused himself from the case, which had passed through the U.S. Court of Appeals for the D.C. Circuit, where he previously served.