VIGILANT SHIELD 2008 is a Chairman of the Joint Chiefs of Staff-designated, North American Aerospace Defense Command (NORAD) and U.S. Northern Command (USNORTHCOM) sponsored, and U.S. Joint Forces Command-supported Department of Defense exercise for homeland defense and defense support of civil authorities missions. Exercise VIGILANT SHIELD 2008 will be conducted concurrent with TOP OFFICIALS 4 (TOPOFF 4), the nation's premier exercise of terrorism preparedness sponsored by the Department of Homeland Security, and several other linked exercises as part of the National Level Exercise 1-08. Purpose: Exercise VIGILANT SHIELD 2008 and National Level Exercise 1-08 will provide local, state, tribal, interagency, Department of Defense, and nongovernmental organizations and agencies involved in homeland security and homeland defense the opportunity to participate in a full range of exercise scenarios that will better prepare participants to prevent and respond to national crises. The participating organizations will conduct a multilayered, civilian-led response to a national crisis. (US NORTHCOM, Fact Sheet - Exercise Vigilant Shield 2008, 2007)