"Since the September 11, 2001 terrorist attacks, considerable concern has been raised because the 19 terrorists were aliens who apparently entered the United States legally despite provisions in immigration laws that bar the admission of terrorists. Fears that lax enforcement of immigration laws regulating the admission of foreign nationals into the United States may continue to make the United States vulnerable to further terrorist attacks have led many to call for revisions in the policy as well as changes in who administers immigration law. Foreign nationals not already legally residing in the United States who wish to come to the United States generally must obtain a visa to be admitted, with certain exceptions noted in law. Prior to establishment of the Department of Homeland Security (DHS), two departments -- the Department of State (DOS) Bureau of Consular Affairs and the Department of Justice (DOJ) Immigration and Naturalization Service (INS) -- each played key roles in administering the law and policies on the admission of aliens. Although DOS Consular Affairs remains the agency responsible for issuing visas, DHS' Bureau of Citizenship and Immigrant Services approves immigrant petitions, and DHS's Bureau of Customs and Border Protection inspects all people who enter the United States. In FY2002, DOS issued approximately 6.2 million visas and rejected over 2.2 million aliens seeking visas. The President's proposal for DHS, H.R. 5005 as introduced, would have bifurcated visa issuances so that DHS would set the policies, giving the DHS Secretary exclusive authority through the Secretary of State to issue or refuse to issue visas and retaining responsibility for implementation in DOS."
CRS Report for Congress, RL31512