<Li> Bo De River, Nha Trang, Tha Cau River </Li> <P> Operation Rolling Thunder was the title of a gradual and sustained aerial bombardment campaign conducted by the U.S. 2nd Air Division (later Seventh Air Force), U.S. Navy, and Republic of Vietnam Air Force (VNAF) against the Democratic Republic of Vietnam (North Vietnam) from 2 March 1965 until 2 November 1968, during the Vietnam War . </P> <P> The four objectives of the operation (which evolved over time) were to boost the sagging morale of the Saigon regime in the Republic of Vietnam, to persuade North Vietnam to cease its support for the communist insurgency in South Vietnam without actually taking any ground forces into communist North Vietnam, to destroy North Vietnam's transportation system, industrial base, and air defenses, and to halt the flow of men and material into South Vietnam . Attainment of these objectives was made difficult by both the restraints imposed upon the U.S. and its allies by Cold War exigencies and by the military aid and assistance received by North Vietnam from its communist allies, the Soviet Union, the People's Republic of China (PRC) and North Korea . </P> <P> The operation became the most intense air / ground battle waged during the Cold War period; it was the most difficult such campaign fought by the United States since the aerial bombardment of Germany during World War II . Supported by communist allies, North Vietnam fielded a potent mixture of sophisticated air - to - air and surface - to - air weapons that created one of the most effective air defenses ever faced by American military aviators . </P>

What was the purpose of the operation rolling thunder