A view of the Al-Na'im traffic circle after its liberation in Raqqa, Syria, in 2017. The location was used by ISIS to perform public executions. (Youssef/Epa-Efe/Rex/Shutterstock/Youssef/Epa-Efe/Rex/Shutterstock)

The government cannot “forcibly — and irrevocably — transfer” an American citizen and suspected Islamic State member held in U.S. custody in Iraq to a third country, a federal appeals court ruled in an opinion made public Wednesday.

The 2-to-1 decision upholds an earlier ruling that blocked the imminent transfer of the man, who has been held without charges for more than seven months after he was captured in Syria and handed over to U.S. forces.

The case before the U.S. Court of Appeals for the D.C. Circuit has raised novel questions about how the court balances national security interests with the constitutional rights of individual citizens.

“We know of no instance — in the history of the United States — in which the government has forcibly transferred an American citizen from one foreign country to another,” wrote Judge Sri Srinivasan, who was joined by Judge Robert L. Wilkins. “There is all the more reason, then, to proceed with considerable caution before recognizing such a power as unilateral.”

In its 45-page ruling, the court says allowing the government to make such a move could open the door to troubling scenarios for other U.S. citizens traveling overseas as journalists or tourists.

The government does not have the power to “seize any American citizen voluntarily traveling abroad for forcible transfer to any country with some legitimate sovereign interest” in that person, the opinion said.

In her dissent, Judge Karen LeCraft Henderson wrote that the court’s ruling disrupts military operations and U.S. relations with other countries. The decision, she wrote, “portends a hazardous expansion of the judiciary’s role in matters of war and diplomacy.”

The Trump administration has said the law provides the U.S. military with broad discretion when it comes to battlefield operations, including the transfer of people captured overseas. In this case, the man voluntarily traveled to Syria.

A Justice Department spokeswoman said the government is considering its options.

The man’s attorneys, from the American Civil Liberties Union, say he has the right as a citizen to challenge his detention and must either be charged with a crime or released.

Attorney Jonathan Hafetz, who is representing the man, said Wednesday that the ruling affirms that the “executive does not have carte blanche to dispose of the liberty of citizens by indefinite detention or forceable transfer.”

The majority opinion recognizes the government’s wartime powers over enemy combatants and leaves an opening for the government to make the transfer at a later date.

The ruling notes that the court’s decision would have been different if it had already determined the man in custody is legally subject to detention. At this early stage in the litigation, the court said, the government has not shown it has that authority.

The man’s case has presented legal challenges for the government. Justice Department lawyer James M. Burnham said in court last month there is evidence the man — who has not been publicly identified — joined or “substantially supported” the Islamic State. U.S. officials have said, however, they lack admissible evidence to charge the man with a crime and therefore want to move him from Iraq to a third country.

The name of the receiving country has not been made public, but the man is a dual citizen of the United States and Saudi Arabia. Court records referring to repatriation and Saudi law suggest that the receiving country would be Saudi Arabia.

The case initially reached the D.C. Circuit after U.S. District Judge Tanya S. Chutkan required the government to provide 72 hours’ notice before making such a transfer. The Defense Department gave notice on April 16 of plans to move the man, and the judge then stopped the transfer, prompting a second appeal by the government.

The ruling made public Wednesday also upheld the 72-hour notice requirement imposed by the lower-court judge.