Military Commissions Act

The Military Commissions Act was a law passed in the United States in 2006 to provide rules and regulations for how to treat and try "illegal alien combatants".

This was made necessary by the George W. Bush administration's decision that fighters picked up abroad were not POWs, and terrorists abducted by the military/CIA/etc. were no longer normal criminals. The Bush administration did not want to provide Geneva protections to the former, or due process to the latter. This is not technically a violation of the Geneva Convention because it only applies to what it defines as a "lawful combatant", which is essentially a uniformed fighter with a defined chain of command. In theory, any non-lawful combatant can be treated at the discretion of the country that captured him/her, however it has almost always been practice to treat the person as a POW, but nothing has been officially written about this in most countries, including the US. Eventually, however, rules of some kind were needed, and the Supreme Court had left it up to Congress to make them.

The law was written by the Republican Party leaders, especially Mitch McConnell. The law specifically ruled that the status of such combatants would be determined not by a court, but by a special tribunal to be selected by the President. Moreover, there could not be any appeal of this determination. Even the right of habeas corpus has been removed.

In theory, this means that if the President and his handpicked tribunal wished to, they could abduct anyone and have that person declared an "enemy combatant," with no opportunity for the person to argue their case before an independent judge. In practice, this will only happen to Middle Eastern people the administration finds scary.

Update
It was amended by the which gave prisoners slightly more rights.