"There is no 'just war'"

[gratuitous]

4. It follows along the same lines as torture or the death penalty

As long as there are one or two "except for" loopholes, look for the powers that be to try to shoehorn any situation into one of those exceptions. Whether it's the ticking time bomb scenario (ridiculous on its face) or the particularly heinous murder, the temptation is there for the jailer or the prosecutor to figure out how the case at hand merits the exception. Whether it's a "1% doctrine" or the "unknown unknowns" or some other bit of locutional legerdemain, there's going to be the golden exception that says this creep needs to be waterboarded or that killer was extra depraved.

By the same token, as long as there is a theory of "just war" floating around out there, the warmongers will tailor their case for war to fit under the just war rubric even if it's total nonsense. It's human nature. We should indeed jettison this primitive relic of a bygone era; we've seen it abused too many times over the centuries to pretend that it's a benign philosophical point.