reports that the U.S. Court of Appeals for the District of Columbia has overturned the conviction of Salim Hamdan, Osama Bin Laden’s driver.

The U.S. Court of Appeals concluded that the Military Commissions Act did not authorize prosecutions for conduct that occurred before the law was passed and that was not prohibited at the time it occurred.

Hamdan was captured in Afghanistan in November 2001.

In 2006, the U.S. Supreme Court overturned the Guantanamo court system.  After this Supreme Court decision, Congress passed the Military Commissions Act of 2006, which created  specific new war crimes that could be prosecuted by a military commission, including providing support for terrorism.