Rand has posted the final report of their Counterinsurgency Study series. The central question the study attempted to answer was "How should the United States improve its capabilities to counter insurgencies, particularly those that are heavily influenced by transnational terrorist movements and thus linked into a global jihadist network?"
War by Other Means -- Building Complete and Balanced Capabilities for Counterinsurgency. RAND Counterinsurgency Study -- Final Report
http://www.rand.org/pubs/monographs/2008/RAND_MG595.2.pdf