In the past two weeks, the Court of Appeals for the District of Columbia Circuit has handled two cases raising important questions of the scope of executive power to detain citizens without any judicial supervision.  The two cases, Omar v. Harvey and Munaf v. Harvey, concern U.S. citizens detained in Iraq.  Perhaps because the strife-torn circumstances of Baghdad seem so far away from normality, the government’s claim to unchecked detention power in these cases has aroused little attention.  But the arguments in play have a far broader scope than just wartime detention.

Since the first Judiciary Act, federal law has contained a guarantee of habeas corpus.  Any citizen detained by the federal government could thus approach a federal court and seek review of his lock-up.  To be sure, there have been moments when a president refused to obey the federal courts.  Most famously, Lincoln declined to obey Chief Justice Roger Taney in the Merryman case.  But the governing rule has been that habeas exists to protect the citizen’s liberty at all times.  When U.S. troops and their dependents began being stationed overseas in large numbers after World War II, the question arose whether citizens carried their constitutional shield with them.  The Supreme Court in a series of cases involving military trials overseas was unequivocal:  A citizen had a judicially enforceable right to be free of lawless detention by her own government regardless of where she was in the world.

In both Omar and Munaf, Justice Department lawyers made a simple yet sweeping argument:  The United States can act as a jailor of its own citizens without any judicial review provided it wears a “multinational