Department of Homeland Security's (DHS) Immigration Interior Enforcement Strategy's implementation is now the responsibility of the Bureau of Immigration and Customs Enforcement (BICE). This strategy was originally created by the Immigration and Naturalization Service (INS). In the 1990s, INS developed a strategy to control illegal immigration across the U.S. border and a strategy to address enforcement priorities within the country's interior. In 1994, INS's Border Patrol issued a strategy to deter illegal entry. The strategy called for "prevention through deterrence"; that is, to raise the risk of being apprehended for illegal aliens to a point where they would consider it futile to try to enter. The plan called for targeting resources in a phased approach, starting first with the areas of greatest illegal activity. In 1999, the INS issued its interior enforcement strategy designed to deter illegal immigration, prevent immigration-related crimes, and remove those illegally in the United States. Historically, Congress and INS have devoted over five times more resources in terms of staff and budget on border enforcement than on interior enforcement. INS's interior enforcement strategy was designed to address (1) the detention and removal of criminal aliens, (2) the dismantling and diminishing of alien smuggling operations, (3) community complaints about illegal immigration, (4) immigration benefit and document fraud, and (5) employers' access to undocumented workers. These components remain in the BICE strategy. INS faced numerous challenges in implementing the strategy. For example, INS lacked reliable data to determine staff needs, reliable information technology, clear and consistent guidelines and procedures for working-level staff, effective collaboration and coordination within INS and with other agencies, and appropriate performance measures to help assess program results. As BICE assumes responsibility for strategy implementation, it should consider how to address these challenges by improving resource allocation, information technology, program guidance, and performance measurement. The creation of DHS has focused attention on other challenges to implementing the strategy. For example, BICE needs to coordinate and collaborate with the Bureau of Citizenship and Immigration Services (BCIS) for the timely and proper adjudication of benefit applications, and with the Bureau of Customs and Border Protection (BCBP) to assist in antismuggling investigations and sharing intelligence. In addition, BICE needs to assure that training and internal controls are sufficient to govern investigators' antiterrorism activities when dealing with citizens and aliens.