国会研究服务部-美国移民政策入门（英）-副本.docx

Primer on U.S. Immigration Policy Updated July 1, 2021 Congressional Research Service R45020 Primer on U.S. Immigration Policy U.S. immigration policy is governed largely by the Immigration and Nationality Act (INA), which was first codified in 1952 and has been amended significantly several times since. U.S. immigration policy contains two major aspects. One facilitates migration flows into the United States according to principles of admission that are based upon national interest. These broad principles currently include family reunification, U.S. labor market contribution, origin-country diversity, and humanitarian assistance.  SUMMARY R45020July 1, 2021 R45020 July 1, 2021 William A. Kandel Analyst in Immigration Policy immigration occurs through family and employer-sponsored categories, the diversity immigrant visa lottery, and refugee and asylee admissions. Temporary immigration occurs through the admission of foreign nationals for specific purposes and limited periods of time, and encompasses two dozen categories that include foreign tourists, students, temporary workers, and diplomats. The other major aspect of U.S. immigration policy involves restricting entry to and removingpersons fromthe United States who lack authorization to be in the country, are identified as criminal aliens, or whose presence in the United States is determined to not serve the national interest. Such immigration enforcement is broadly divided between border enforcement—at and between U.S. land, air, and sea ports of entry—and other enforcement tasks including interior enforcement, detention, removal, worksite enforcement, and combatting immigration fraud. The dual role of U.S. immigration policy—admissions and enforcement—creates challenges for balancing major policy priorities, such as ensuring national security, facilitating trade and commerce, protecting public safety, and fostering international cooperation. Congressional Research Service Primer on U.S. Immigration Polic