"The events of September 11, 2001 caused the nation's leaders to accelerate existing border programs aimed at prevention. Traditionally, the 'prevention' of border violations has involved interdiction (physically impeding any incursion while it is occurring), preemption (through routine screening to intercept illegal shipments, weapons, people, or other illicit cargo), and deterrence (where an action taken means a potential violator does not plan or even attempt an illegal entry). While effective in some cases, none of these strategies - together or separately - has evolved into a comprehensive, prevention oriented approach to border security. The development of a prevention-led border strategy would involve at least four strategic shifts: aligning border security with global strategy; forging a new foreign policy; making progress on cooperation; and changing U.S. reactive approaches."
2005 Naval Postgraduate School (U.S.). Center for Homeland Defense and Security. Posted here with permission. Documents are for personal use only and not for commercial profit.
Homeland Security Affairs Journal: http://www.hsaj.org/hsa/
Homeland Security Affairs (Summer 2005), v.1 no.1, article 2