American citizen Abdulrahman Ahmad Alsheikh was apprehended in Syria and turned over to U.S. authorities on suspicions that he was a member of the Islamic State militant group. Alsheikh was held for more than a year but he was never charged, nor did he face a trial before his release in October. The U.S. government obviously felt insecure about the wartime legal authorities it uses, without congressional authorization, against ISIS members. By releasing Alsheikh, the government avoids a possible court ruling against such authority.

After 9/11, George W. Bush began jailing terrorism suspects. These included U.S. citizens, as in the famed case of Jose Padilla. The government defined these suspects as enemy combatants and held them indefinitely without trial instead of prosecuting them in civilian courts. The extent of the government’s power to detain such suspects has never been adequately adjudicated by the courts.

There are several reasons to believe the U.S. Constitution bars a government from detaining U.S. citizens indefinitely without letting them challenge their detention (filing a writ of habeas corpus). The Bush administration purposefully used the term “enemy combatants” to create a juridical gray zone in which terrorism suspects were denied rights under the Geneva Conventions and were denied the rights of habeas corpus and a civilian jury trial under the U.S. Constitution. Of course, the Geneva Conventions are called into cause during a war. The U.S. is involvement in Syria is backed by no declaration of war and by no other congressional vote of approval, making its definition as a war legally questionable.

In fact, the only Islamist militant groups the U.S. military has been authorized by Congress to fight are the main al Qaeda group in Afghanistan and Pakistan, whose members attacked the United States on 9/11, and the Afghan Taliban, who harbored the members of that al Qaeda group. No congressional authorization exists to use the U.S. military to attack other al Qaeda affiliates or former affiliates, including ISIS, around the world. Many members of Congress know that the military actions spanning the globe from Syria and Libya to Niger and Yemen stand on shaky legal ground. Alsheikh’s release shows that the Trump administration implicitly may be admitting the same.

Because no war technically exists in Syria, a U.S. citizen such as Alsheikh should have been brought to the United States to face charges and a jury trial. And because the U.S. Constitution implies that only Congress, and not the president, can suspend habeas corpus in times of invasion or insurrection, Alsheikh should have been able to challenge his detention in a civilian court. Yet U.S. prosecutors were scared that if they brought him to the United States for trial and the judge found their evidence of his material support to ISIS to be inadmissible, they would be required to release him on U.S. soil. The evidence on record suggests that Alsheikh’s involvement with ISIS may have been limited to administrative work and menial tasks—he probably was not a fighter.

Although the Trump administration recoiled in fear at this possibility, Alsheikh’s threat to the United States in that eventuality seems to have been exaggerated—after all, he had been in the United States before and not attacked anyone or anything. Releasing Alsheikh was the right thing to do, even if done for the wrong reason. However, holding a U.S. citizen in jail for more than a year without charges and a jury trial is unconstitutional during peacetime.