The president isn’t claiming too much power to claim Americans who join Al Qaeda, but too little
Where the white paper commits serious error is in positing that the “due process” clause of the Fifth Amendment applies to al Qaeda operatives at large. In Hamdi v. Rumsfeld (2004), the Supreme Court ruled that once suspected enemy combatants had been captured and detained, some measure of “process” was owed to them. But the court’s decision applied to enemy combatants only after their capture, but not before it. The distinction makes perfect sense. It would be shocking to give a captured enemy combatant a drumhead trial on charges of committing war crimes and then shoot him moments later. But minutes before being captured, that same enemy combatant would have been a lawful target for lethal fire. Enemies reduced to captivity do not pose anything like the degree of danger of those under arms and at large.
The white paper’s assumption that U.S. citizens who are enemy combatants are constitutionally entitled to due process even while engaged in, or available for, hostilities is both gratuitous and in error. It is not compelled by the language of the due process clause, which protects “persons,” not “citizens.” If the white paper were right in claiming that U.S. nationals in al Qaeda deserved due process rights, then it should logically have concluded that the same was true of Saudis or Yemenis in al Qaeda. Further, the white paper’s extension of due process to enemy combatants at large is not dictated by any Supreme Court decision. It also has no basis in the traditional laws of war or state practice. And it carries significant operational disadvantages.