Just to be clear, the magnitude of Hillary's evilness (which no one here can dispute and most of us probably even underestimate) has nothing to do with double effect.
Well, yes and no. Magnitude is a key part of condition 3 of double effect, for e.g. if I'm deciding whether or not to strike enemy headquarters during a just war, the likely number of innocent civilians (none of whose deaths are intended, but only foreseen as inevitable, due diligence to minimize which number is absolutely mandatory) who will be collateral damage is an essential criterion. If we can strike the enemy decisively, say, kill 1000 enemy combatants per 1 innocent civilian who unfortunately perishes while the war ends as soon as possible, instead of many lives being lost through no one repelling the unjust aggressor, as the Popes hoped in launching the Crusades while the Turks were unjustly attacking Christians and churches, it will be lawful to accept that unintended secondary effect. But if, as modern тαℓмυdic Israel does, we kill 10 combatants and 1000 civilians - taking no effort whatsoever to mitigate that consequence and therefore morally responsible for it - that's manifestly illicit and a grave violation of the proportionality necessary for double effect to apply. That's what I meant by magnitude of evil.
I see what you're getting at, though, Lad, you mean we can't directly and intentionally target a single innocent civilian if this would save 1000s of lives, which is absolutely true. So, even if directly targeting 10 innocent babies for killing in an orphanage on enemy territory would utterly demoralize and terrorize them into surrendering, it would never ever be lawful to intend it, and to deliberately perpetrate such a heinous deed would be criminal. It would be a violation of just conduct during war - the second part to completing a war justly - even if the war was originally just to begin with, in that it was defense against an unjust agressor. This would be terrorism in the true sense. Islam, for instance, has never made and appears not to have ever comprehended that distinction, which explains why they believe anything goes during their endless jihad against the Church; while Christian theologians and philosopehrs have. Unlike ends-justifies-the-means, which as you noted, originated with Protestants and naturalists like Jeremy Bentham and other utilitarian philosophers, and in varying forms was taken first by the agnostic French revolutionists and next the godless Communists to terrible lengths, double-effect is a Thomistic principle, enjoys the official approbation of the Catholic Church, and is still enshrined in international law owing to Christianity's influence on western civilization. Its important to have our moral principles right, as decline in morals almost inevitably means decline in faith.
Let's see how the election turns out.