From "Six Questions for Louis Fisher, Author of The Constitution and 9/11" by Scott Horton at Harper's:
The Bush Administration repeatedly insisted that the president had “inherent authority” to create military tribunals to enforce the laws of war against enemy combatants. It suggested that there was therefore no need for the President to obtain congressional authorization for the commissions at Guantánamo. They cite the example of the trial of Major André during the Revolutionary War. Are they right about this?Read the other five exchanges.
Remarkably, the Justice Department argued in court that part of President Bush’s inherent authority to create military tribunals can be traced back to the 1780 trial of Major André. General George Washington did indeed appoint a Board of General Officers to try André as a spy, but anyone with a smattering of American history would know that you cannot derive presidential power from precedents set in 1780. There was no President at the time other than the presiding officer of the Continental Congress. There was not even an executive branch. There was one branch of government: the Continental Congress, exercising legislative, executive, and judicial powers.
The Justice Department insisted “there was no provision in the American Articles of War providing for the jurisdiction in a court-martial to try an enemy for the offense of spying.” That is false. The Continental Congress adopted a resolution in 1776 expressly providing that enemy spies “shall suffer death… by sentence of a court martial, or such other punishment as such court martial shall direct,” and ordered that the resolution “be printed at the end of the rules and articles of war.” The previous year, Congress had made it punishable by court-martial for members of the Continental Army to “hold correspondence with” or “give intelligence” to the enemy. General Washington acted on the basis of legislative authority, not some sort of “inherent” executive authority cited so frequently by the Bush Administration.