In the quest to bring perpetrators of massive crimes to justice, international courts should be considered only as a last resort. Efforts to establish rule of law require the development of national capacity to prosecute the most serious crimes. On 25 and 26 October 2012, leading international actors from the judicial, rule of law, and development sectors will convene at the Greentree Estate in Manhasset, New York for the third Greentree Conference on Complementarity. The meeting aims to examine the needs of and challenges to national prosecutions for the most serious crimes in four countries: Ivory Coast, the DRC, Colombia, and Guatemala.