One of the most controversial and important topics in American politics is the security of its borders. Over the last two years, the system has been overwhelmed by large numbers of entrants. How does the U.S. government protect its borders? Why are we experiencing such an increase in border activity?

America is a nation of immigrants. Virtually all of us can trace our ancestry to people who immigrated to the United States. Even so, immigration is a controversial issue, particularly in the case of unauthorized immigration, where individuals enter or reside in the United States in violation of the law. How many individuals in the United States are unauthorized? Does unauthorized immigration have negative consequences, such as an increase in crime? This brief focuses on unauthorized immigration; there are links in the Further Reading section to other immigration-related topics such as Authorized Immigration, Refugees and Asylum, and Border Security.

If you are wondering what a green card is and what criteria are used to determine who gets one, then you are wondering about the United States’ policies on authorized immigration. An authorized immigrant is a noncitizen born in another country who has received formal permission to live and work in the United States. Green cards are the most visible indicator of the complex rules and processes that determine who can immigrate to the US and who cannot. Often, the term ‘immigration’ is used to describe both legal (authorized) immigration and illegal (unauthorized) immigration. This brief focuses on authorized immigration, or immigration to the US that is allowed by the US government. (For information on unauthorized immigration and other aspects of immigration policy, see the For Further Reading section at the end of this brief.)