Nearly three months have passed since the U.S. military took custody of an American citizen believed to be an Islamic State fighter. Since early September, the Defense Department has detained the man in Iraq without making public the most basic information about his identity or his case. Disturbingly, it’s not even clear whether he knows of his constitutional right to contest his detention in court.

The detainee allegedly fought alongside the Islamic State in Syria, where he was captured by Syrian rebel fighters on Sept. 12 and handed over to U.S. forces. Reporting suggests that his continued detention may stem from the government’s uncertainty over whether the case against him would be strong enough to win a conviction in U.S. criminal court. But extended military detention could spark a court battle over the government’s authorization to use force against the Islamic State.

The detainee’s future might be complicated. What’s not complicated is his constitutionally guaranteed right to habeas corpus. If he wishes it, the government must allow him access to the justice system to make a case against his detention with a lawyer’s help. Yet while the Justice Department says the man asked for a lawyer before being questioned as part of a criminal case, it also suggests that he hasn’t been informed of his habeas rights. The government reasons that it can withhold those rights until it makes up its mind as to the detainee’s fate.

Because the man remains anonymous, there’s no way to identify family members who could sue on his behalf — or determine whether those family members are already aware of his detention and have chosen not to litigate. To fill the gap, the American Civil Liberties Union has filed suit on the man’s behalf. But the Justice Department is arguing that the ACLU can’t represent the detainee without his or his family’s approval. While it’s true that courts don’t usually allow third parties to jump into lawsuits on behalf of others, they also shouldn’t let the government effectively block a prisoner’s access to the justice system by keeping his identity secret.

To be sure, the government isn’t arguing that it can put off the man’s exercise of his habeas rights forever. And courts have ruled in the years since 9/11 that a detainee captured on the field of battle need not receive immediate access to counsel. But at this point, more than two months have passed without the government making any case for why this delay is necessary or constitutional.

If the detainee has already been in contact with a lawyer — or if he has decided he doesn’t want one — the government should make that clear. It should also make clear whether his relatives know of his detention and of their own right to litigate in his stead. And if that’s not the case, the judge should allow the ACLU to make contact with its potential client so he has the chance to have his day in court.

Editorial by The Washington Post