Book excerpt: A longtime CNN columnist astutely combines history and global politics to help us better understanding the exploding number of military, political, and diplomatic crises around the globe. The riveting and illuminating behind-the-scenes stories of the world's most intense “red lines," from diplomatic and military challenges at particular turning points in history to the ones that set the tone of geopolitics today. Whether it was the red line in Munich that led to the start of the Second World War, to the red lines in the South China Sea, the Korean Peninsula, Syria and the Middle East. As we traverse the globe, Andelman uses original documentary research, previously classified material, and interviews with key players, to help us understand the growth, the successes and frequent failures that have shaped our world today. Andelman provides not just vivid historical context, but a political anatomy of these red lines. How might their failures be prevented going forward? When and how can such lines in the sand help preserve peace rather than tempt conflict? A Red Line in the Sand is a vital examination of our present and the future—where does diplomacy end and war begin? It is an object lesson of tantamount importance to every leader, diplomat, citizen, and voter. As America establishes more red lines than it has pledged to defend, every American should understand the volatile atmosphere and the existential stakes of the red web that encompasses the globe.