Tensions with Mexico, then in the throes of a violent civil war, escalated almost to the point of warfare. The U.S. sent military forces to chase Pancho Villa and to control the port of Vera Cruz. In 1917 both parties pulled back, and by 1920 the civil war was over. | Tensions with Mexico, then in the throes of a violent civil war, escalated almost to the point of warfare. The U.S. sent military forces to chase Pancho Villa and to control the port of Vera Cruz. In 1917 both parties pulled back, and by 1920 the civil war was over. |