The main purpose of this legislation is to establish stricter immigration controls for nationals of the People's Republic of China. It aims to ensure that no individual from China can enter the United States without a valid visa. This is part of a broader effort to tighten security and manage immigration from specific countries deemed to pose a higher risk. Key provisions of the legislation include a clear prohibition against admitting any national of China who does not possess a valid visa. This means that individuals from China cannot enter the U.S.