In the wake of the 9/11 terrorist attacks in New York and Washington D.C., a bipartisan group of Congress proposed a radical restructuring of the U.S. federal agencies to address issues of U.S. security and passed The Homeland Security Act of 2002. The act established a new agency, the Department of Homeland Security, or DHS.
DHS inherited approximately 200,000 federal employees from 22 federal agencies and began with a budget of $37 billion. It was the largest department created since the Department of Defense in 1947.
The new department radically changed how the U.S. enforces immigration law. The Immigration and Naturalization Service (INS), an agency within the Department of Justice, had previously overseen the enforcement of immigration laws. The Homeland Security Act dismantled INS and broke it into three agencies within DHS: U.S. Customs and Border Protection, U.S. Immigration and Customs Enforcement, and U.S. Citizenship and Immigration Services. Several other agencies related to border and customs inspections were also transferred to DHS.