Final answer:
The U.S. interest in South Vietnam during the late 1950s centered around supporting President Ngo Dinh Diem's government with military and economic aid to create a non-Communist state, despite Diem’s oppressive regime that led to widespread unpopularity and dissent.
Step-by-step explanation:
United States Involvement in South Vietnam in the Late 1950s
During the late 1950s, the United States interest in South Vietnam was largely based on the establishment of a non-Communist state that could offer an alternative to H_o Chi Minh's government in North Vietnam. The U.S. supported Ngo Dinh Diem, hoping he would establish a democratic and prosperous South Vietnam. However, Diem became increasingly autocratic, cancelled the scheduled 1956 elections, and grew unpopular, particularly among Buddhists, students, and farmers.
Despite the tyranny, corruption, and the resulting unpopularity of Diem's regime, the United States continued to supply military and economic aid, with the belief that a non-Communist Vietnam was vital to preventing the spread of communism in the region. This commitment to Diem’s government persisted even as his oppressive actions led to widespread dissent and strengthened the insurgency led by the National Liberation Front and North Vietnam.