Naturalization is the process by which United States of America citizenship is granted to a lawful permanent resident after meeting the requirements established by Congress in the Immigration and Nationality Act (INA). A person with a dual citizenship is a citizen of two countries at the same time, which has advantages and disadvantages because it is a complex legal status. Some of the benefits of having a dual citizenship include the ability of an individual to possess two passports, the freedom of access, movement, and money that is not readily available to just the citizen of one country.
Prior to 1906 naturalization proceedings took place in local, municipal, or state court systems. After 1906 the federal courts took responsibility for reviewing and granting United States citizenship. Then in 1991 the Immigration and Naturalization Service (INS) took the responsibility. In 2003 INS ceased to exist and most of its functions were transferred to three entities within the newly created Department of Homeland Security (DHS):