The main purpose of this legislation is to impose a temporary ban on the admission of foreign nationals, referred to as "aliens," into the United States for a period of ten years. The objective is to restrict immigration during this time frame, although the specific reasons for this ban are not detailed in the text. The key provision of this law is straightforward: it prohibits any foreign national from being admitted to the United States for ten years starting from the date the law is enacted. This means that no new immigrants will be allowed to enter the country during this period.