The Immigration and Nationality Act (INA) is a comprehensive law enacted in 1952 that governs immigration and citizenship in the United States. It outlines the processes for obtaining visas, green cards, and citizenship, as well as the criteria for deportation. The INA has been amended several times to address changing immigration needs and policies. The act categorizes immigrants into various groups, such as family-sponsored, employment-based, and humanitarian categories. It also establishes quotas for the number of immigrants allowed from different countries each year, aiming to manage the flow of newcomers while ensuring national security and economic stability.