One of the most important questions here — perhaps the most important — is not what the legal standard is but who ultimately decides whether the standard is satisfied in any given case. Who decides that a particular person presents a threat sufficient to justify the government's summarily killing him? The Justice Department contends that the Constitution permits this decision to be entrusted to an "informed high-level official" — with no judicial review before the killing or even after. This is wrong and dangerous.
The possibility that executive agents will get the facts wrong is not one we should overlook.
The Constitution prohibits the government from depriving a person of his life without due process, and due process requires judicial process, not just executive fiat. The Justice Department's argument that judicial process is infeasible in the context of an armed conflict is an argument that the Supreme Court has already rejected. Even in the context of armed conflict, Justice Sandra Day O'Connor wrote in Hamdi v. Rumsfeld, the Constitution "most assuredly envisions a role for all three branches when individual liberties are at stake."
As others have pointed out, there are good reasons for this. High-level executive officials, however "informed," will make mistakes. Some of them will push the limits of their authority, and some of them will exceed it. The white paper doesn't say by whom the high-level officials will be informed, or what it is that they will be informed of, but the possibility that executive agents will get the facts wrong is not one we should overlook. To understand the risk, one need only look to our experience with Guantanamo, where, on the orders of "informed high-level officials," hundreds of men were imprisoned on the basis of evidence that turned out to be fabricated, unreliable or mistaken.
The debate about the legal standards is important. But the white paper's most disturbing passage is the one that contends, without serious analysis, that the courts have no role to play in assessing whether those standards are being met.