First and foremost: ALL governments are forged from rebellion. The type of rebellion may change, it can be peaceful or violent but ALL of them come from rebellion.
The Constitution specifically provides a mechanism for the peaceful replacement of the US government through elections, that's what separated thar document from the other governments of the time. (Whether we sheeple will do it to take the current crop of ticks off our collective hide is another discussion entirely.)
Enough of that. The Constitution grants Congress the power to do certain things.
'To define and punish Piracies and Felonies committed on the high Seas, and Offences against the Law of Nations;'
That last part is the important one. It means Congress can uphold international law.
Treason was specifically defined.
'Treason against the United States, shall consist only in levying War against them, or in adhering to their Enemies, giving them Aid and Comfort. No Person shall be convicted of Treason unless on the Testimony of two Witnesses to the same overt Act, or on Confession in open Court.
The Congress shall have Power to declare the Punishment of Treason, but no Attainder of Treason shall work Corruption of Blood, or Forfeiture except during the Life of the Person attainted.'
From Wiki:
The Constitution does not itself create the offense; it only restricts the definition (the first paragraph), permits Congress to create the offense, and restricts any punishment for treason to only the convicted (the second paragraph). The crime is prohibited by legislation passed by Congress. Therefore the United States Code at 18 U.S.C. § 2381 states "whoever, owing allegiance to the United States, levies war against them or adheres to their enemies, giving them aid and comfort within the United States or elsewhere, is guilty of treason and shall suffer death, or shall be imprisoned not less than five years and fined under this title but not less than $10,000; and shall be incapable of holding any office under the United States."
I'd venture to say anyone who, as in the case of that Awaliki guy, decided to commit treason should have studied that paragraph first and then renounced their US citizenship. Had he done that, maybe he might still be alive and able to fight the Great Satan.
So we come to public accountability. Now we return to the whole problem of terrorists using the laws of the US against itself. Remember how the lawyers wanted the 9/11 mastermind Khalid Sheik Mohammed tried in New York? That was a blatant attempt to incite the populace.
Then think of the introduction of evidence; now you are talking about putting people on the witness stand who could quite likely lose their lives for having a part in his capture. Much like the Mafia used to do, the terrorists wouldn't bother with such niceties as due process. So how should we protect those people who put their lives on the line to protect the sheeple?
At least KSM is still alive in his legal limbo. His boss OBL is dead (BTW, wasn't he deprived of due process as well by Seal Team Six operating under orders from Obama?) as is Awaliki.
Those shades of gray keep changing, don't they? BTW, speaking of shades of gray: How about the recent bustup of that big Russian spy ring?
http://abcnews.go.com/blogs/politics/2011/11/how-the-fbi-busted-anna-chapman-and-the-russian-spy-ring/ They were tried and deported, that Chapman girl has gone on to become quite the sensation in her homeland.
What's the connection? The Espionage Act provides for the death penalty for anyone caught interfering with the operations of the US military, to include disclosing information to another government. The big difference? They didn't fly planes into buildings so they were given a literal slap on the wrist instead of the gallows or riding the lightning.
There's those pesky shades of gray again.