"The purpose of this paper is to discuss current issues regarding the use of the National Guard in response to Incidents of National Significance (INS). It will address the background of the Department of Homeland Security in the United States, with a focus on the National Guard's role relative to the broader Defense Support to Civilian Authorities mission during an INS. It will include a discussion regarding the Emergency Management Assistance Compacts as a mechanism for employing the National Guard across state borders, and contrast that with using the National Guard in a Federalized status. Hurricane Katrina, the first INS to occur under the National Response Plan, generated a large response from various state and Federal agencies, including the National Guard. This enabled the identification of several issues that impacted on the ability of the National Guard to respond. Two changes to statute made since the response to Hurricane Katrina are described, and their effectiveness is analyzed. Several issues that remain to be addressed are discussed. The paper concludes with four recommendations intended to facilitate a more timely, effective, and efficient response in the event of future INS."