Deut. 32.8 said:
How would you apply that dictum to the Gestapo in Germany and Eastern Eyrope or the Janjaweed in Darfur?
Since the axiom dictates what is going on in Sudan (and I think you're referring to the Ukraine) and the Ukraine is wrong, we should respond.
In the latter case, the we should apply pressure for a whole new elections with stricter rules. Other than that, nothing. Sometimes all we can do is "Do no harm." If we forcibly put in the candidate favored by the West, then the rest of Eastern Europe will wall up, and worse, there could be a civil war. If we suddenly jumped ship to the incumbant, then there could well be a civil war, and we just abandoned the ones our nations supported. If we do not act, there is a chance of civil war.
I'm hoping that another election with stricter rules, and outside parties (from both Russia and the West) would look in. I would say "disinterested parties," but there are none.
With reference to Darfur, I'm less informed. As I understand it, the Sudanese government has been arming the various tribes in order to have them perform the dirty work, and then they can say "I'm sorry, we don't have control of the people."
Basically, we have the U.N. It's not the best of institutions, but I can see no other tool. The first thing I can think of is an offer that would reward the Sudanese government for reversing it and actually disarming the tribes. Unfortunately, I can't see those having much effect. After all, if they were thinking of the good of their country and not their particular race, this wouldn't be a problem. Instead, coupled with a U.N. ultimatum, one with special force towards the leaders, it could make it the "most profitable" alternative.
I'm no big fan of the U.N., but I can't think of a better tool here.
I wish I had better answers, but I don't. Sometimes, it seems that the only choices available are the ones that do the least harm.