During 1965 the Vietnam War was transformed into an American War. 'Escalation' brought the deployment of increasing numbers of United States ground troops, and a slowly expanding air campaign against North Vietnam. Yet the war was 'limited' in more senses than one. It was not allowed, either by President Johnson or by the leaders of the Soviet Union and China, to lead to a wider confrontation in other parts of the world; not even, as a 'big unit' war on the ground, to spread beyond the borders of Vietnam.