The accusations are utterly false. The U.S. Constitution explicitly authorizes the use of military force against U.S. Citizens engaged in belligerenciees as a member of hostile enemies.
Please tell me where it says that in the Constitution.
Article III, section 3, clauses 1 and 2 specifically speaks to how those citizens enraged in treason against the US should be handled and it’s through a legal process. Here is what it says:
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.