What are the capabilities and limitations of domestic intelligence efforts in supporting the homeland security enterprise?

What are the capabilities and limitations of domestic intelligence efforts in supporting the homeland security enterprise?
Regarding such capabilities, do you feel that the U.S. is appropriately structured and resourced to adequately provide timely, accurate, and actionable domestic intelligence to the degree needed to identify and address future challenges.
This paper should provide an examination of the various elements that comprise U.S. domestic intelligence efforts (from local law enforcement and other community/regional assets to national intelligence agencies) and how those entities contribute to supporting the homeland security enterprise by protecting American citizens in a collaborative manner.