The policy of containment set the tone for US foreign policy by focusing on keeping communism and the Soviet Union's influence limited, trying to stop it from spreading. That resulted in attempts to block the expansion of communism throughout the Korean peninsula (the Korean War) as well as in Vietnam and Southeast Asia (the Vietnam War).
It was to basically destroy everything the south had, they would do it because it would leave the south short handed on supplies such as food, water, etc
