Thirty years ago, Rwanda’s government began a campaign to eradicate the country’s largest minority group. This Why It Matters episode discusses how in just one hundred days, 800,000 people in Rwanda were killed, while the rest of the world sat on the sidelines.

In this special series of The President’s Inbox on climate change, Paul J. Angelo, the director of the William J. Perry Center for Hemispheric Defense Studies at the National Defense University, sits…