Judge Richard Posner is guest blogger over at lessig blog. He's had several posts on the topic "Break Up the CIA?" which I hastened to comment upon, suggesting that he was Screwing-up the Lede. He responded, and I replied at length, which I reproduce here.
Your response to my "it's not just about the CIA" comment had two main points: 1) the CIA is the key component of the intelligence establishment and 2) a plan like Senator Robert's to reorganize the 15 agencies would be extremely disruptive.
The evidence appears to indicate that the CIA is important but not valuable. The CIA's failures of analysis are legion and are too numerous to list here. It's not hindsight to point out that well before their most recent failures in Iraq, they failed to correctly analyze the progress of North Korean ballistic missile programs, Indian nuclear weapons programs, Libyan nuclear weapons programs, the Iranian revolution, the Soviet strength in the 80's, the significance of Jihadists prior to '94, etc. The record shows an inability for CIA analysis to be relevant to US strategic interests.
WRT CIA collection, it seems clear that the agency had no significant assets in North Korea or China in the 1950s, in North Vietnam during the 1960s and early 1970s, in the Soviet Union during the entire Cold War, in Iraq in the first Gulf War, or in Jihadist organizations during the 90's.
WRT CIA operations, "covert actions" performed by the agency have too frequently been major failures and public relation disasters (not to mention yielding "blowback"). Supporters of the CIA suggest that their successes are unheralded but this claim is risible: in the credit-hungry and leak-ridden environment inside the beltway, no success, however small, is unheralded for long. Note, for instance, the heavily publicized role for CIA irregular forces in the action against the Taliban, and for missile-wielding Predators in Yemen.
Finally, to your other point, disruption. A preservationist argument can always be made, no matter how bad the current situation. The question is not what disruption will be done by change, but is change required? No doubt you would accept that a drastic reorganization of the intelligence services could be required in some circumstances, despite high transition costs. Are these the circumstances? I suspect they are.