What are some of the challenges that people like Sergio Vieira de Mello and others face in trying to stop genocide?

What does Power mean by “not black boxing history”?

She means don't hide anything from people and be honest about what happened so we can know everything and learn from stuff.

Explanation:

i think i am not 100% sure

One main problem would be that they are involving themselves into these dangerous situations and possibly sacrificing themselves, like Sergio, for a cause that could save many others. They are putting themselves in danger in these situations, and I think that shows a lot about their character. Another challenge that they would face would be to get others on board with them. It’s hard to accomplish something as big as what they are trying to do on your own, so they would need to try and convince other people to take a stand with them and fight against this, but not many people want to do this because it means putting their own lives in danger.