I certainly wouldn't underestimate the power of rationalization and internal dishonesty, when it comes to making ordinary people do awful things.
However, I have to ask: doesn't it suit tyrants to pin the lion's share of the blame on "ordinary people"?
~1% of most populations consists of people with some psychopathic traits. More and more we're seeing that people we thought were "ordinary," and corrupted by circumstance, are actually low-grade psychopaths who take advantage of situations. (See for instance internet trolls.)
This seems to be reflected in tyrannical regimes too. Take a look at your average dictatorship (at least from what I've read about such things), and usually you see a small minority of people actually committing war crimes. Most people don't fight back, or even collaberate; but that's not necessarily because they're sympathetic, so much as scared shitless that they and their families will be disappeared. There is a difference between e.g. turning in a dissident because your family is in danger, and actively going out and killing people for the government. Both are wrong, but the latter betrays enthusiasm rather than just fear and peer pressure, IMO.
But the current trend (among people of my political alignment) is to talk of awareness, and keeping a constant eye on one's self. Recognizing one's own blind spots. Etc. This is not a bad thing at all IMO, but I think it might be a solution to the wrong problem.
Think about it. If I buy computer parts made with Congoese tantalum, for instance, I'm complicit in war crimes. I'm creating demand for something that is made by slave labor. That's wrong. Maybe I rationalize away the implications. ("I need to make money so I can have some impact on society, and actually help people, and these computer parts help me do that - even if they were made by slave labor.")
On the other hand, I am not going out with a machine gun and forcing people to work in tantalum mines. And there is no way in hell I would do that. Even if it was the only way to get a working computer... Or, for that matter, to keep my family safe. That is way beyond my (and most people's) threshold for violating personal ethics.
What I'm going to say now is probably anathema to a lot of liberals, but: I'm starting to think you can't deal with war crimes entirely from the bottom up. That you can't rely on ordinary people to fight back, when a tyrannical regime has tremendous leverage on them. That there is no substitute for making sure that those who personally commit war crimes face consequences - not as a matter of vengeance, but as a matter of deterrence and prevention. Because the kind of people who commit murder in cold blood, or order murder in cold blood, are not the kind of people who will listen when you tell them to watch themselves.
Watching one's self has a place, but I very much doubt that it can be a cure-all.
Then again, I could just be rationalizing...
