Ahmed Abu Khattala was the first person charged and prosecuted in the attacks in Benghazi, Libya, which left four Americans dead, including an ambassador.
As the military commission system has struggled to bring terrorism suspects to justice, civilian courts have been much more effective.
The president’s late-night Twitter message could complicate the case against the man accused in the Manhattan truck attack before it even heads to trial.
A Guantánamo military commission sentenced a Saudi detainee to 13 years in prison for terrorism offenses, even as defense lawyers quit another case before the tribunals.
The military appears to be letting protesters deteriorate past a point that once prompted medical attention. One lawyer called it a new strategy to stop the hunger strikes.
A suspect in the attacks, Ahmed Abu Khattala, will go on trial on Monday in the latest test of the civilian court system’s ability to handle high-profile terrorism cases.