When the President orders anyone to be assassinated even if they are declared a terrorist they will be violating that person Constitutional right for due process, without a trial by his peers, or Testimony of two Witnesses. Further more Congress is the body that is to decide punishment not the president. Art. 3 Section 3 states 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.