Nothing better symbolizes the peacemaking achievements of President Donald Trump than the reported agreement of Serbia and Kosovo to name a disputed lake on their border after the man who brought them together, overcoming centuries of conflict between a Christian majority and Muslim majority nation. First reported in the English Language version of Gazeta Express, a Kosovo-based publication, the naming emerged out the successful discussions mediated by Ric Grenell to normalize economic relations between the two nations. That agreement, which also resulted in Kosovo’s agreement to normalize relations with Israel and Serbia’s agreement to move its embassy to Jerusalem,...