Why Proving War Crimes Is Difficult and Rare

This episode details graphic scenes. Many around the world are calling the indiscriminate attacks on civilians in Bucha, a suburb northwest of the Ukrainian capital, Kyiv, a war crime. But investigating such atrocities is painstakingly complicated. Could one case that resulted in convictions — the genocide in Bosnia in the 1990s — offer lessons on how to proceed? Guest: Roger Cohen, the Paris bureau chief for The New York Times.