In July of 2005, the Secretary of Homeland Security announced a major reorganization of the Department. While many of the proposed changes may be effectuated administratively, some might require legislative action due to limits on reorganization authority under the Homeland Security Act of 2002 (P.L. 107-296). Section 872 of the Homeland Security Act gives the Secretary of Homeland Security the authority to reorganize functions and organizational units within the Department either: (1) independently, 60 days after the Secretary provides notice of such an action to the appropriate congressional committees, or (2) through the President's submission of a reorganization plan. The Secretary, however, may not abolish agencies, entities, organizational units, or functions established or required to be maintained by statute. This report examines the scope of the reorganization authority provided in §872 with a focus on (1) the Secretary's independent authority to reorganize the Department and (2) what is meant by the term organizational units, the basic administrative structures that the Secretary is empowered to "establish, consolidate, alter, or discontinue." This report will be updated as warranted.