The Economist's review of Jung Chang and Jon Halliday's Mao: The Unknown Story (which I have not yet read) notes that the book paints Mao as, "a magalomaniac of unremitting evil." And, "[h]e encouraged the Vietnamese to escalate war with America in order to draw in American troops ..."
Part of the tragedy of war is how it gets started in the first place, often with the connivance of maniacs and blunderers on all sides.
Some of the outcomes and aftermath are on display in Barbara Sonneborn's Regret to Inform. Countless war movies focus on the tragic but this one, in my view, does it best.