Unified Command Plan and Combatant Commands: Background and Issues for Congress [July 17, 2012] [open pdf - 700KB]
"The Unified Command Plan (UCP) and associated Combatant Commands (COCOMs) provide operational instructions and command and control to the Armed Forces and have a significant impact on how they are organized, trained, and resourced--areas over which Congress has constitutional authority. The UCP is a classified executive branch document prepared by the Chairman of the Joint Chiefs of Staff (CJCS) and reviewed and updated every two years that assigns missions; planning, training, and operational responsibilities; and geographic areas of responsibilities to COCOMs. Functional COCOMs operate world-wide across geographic boundaries and provide unique capabilities to geographic combatant commands and the Services while Geographic COCOMs operate in clearly delineated areas of operation and have a distinctive regional military focus. […] Potential issues for Congress include the implications of a strategic shift to the Asia-Pacific region. Another issue is whether there is a need for greater interagency involvement in the UCP development process. A possible area for congressional concern is if Geographical COCOMs have made U.S. foreign policy 'too militarized.' Some have also suggested there might be a need for separate COCOMs apart from the current nine to better address emerging regional and ethnic alignments as well as emerging threats such as cyber warfare. Finally, if Congress believes the current COCOM construct does not meet contemporary or future security requirements, there are proposals for alternative organizational structures that might prove more effective."
CRS Report for Congress, R42077