Immigrating to the United States requires individuals to submit a number of detailed applications to the federal government (CIS). If an immigrant marries a legal citizen in America, he becomes a legal citizen. The process of obtaining citizenship continues to become more difficult (Discovery). To become a citizen, you must be able to demonstrate that you know essential American history and values. Among these are the Constitution, the Star-Spangled Banner, and other important American documents. The laws put in place minimize illegal immigration, but not completely, because no law can completely control and stop it.