The current fight between the Senate Intelligence Committee and the CIA – each accuses the other of spying on it – is part of the deep, continuing struggle between the legislative and executive branches of government over the wide-ranging power of the intelligence agency in the post-9/11 world.

The immediate dispute is about the committee’s lengthy study of the CIA’s harsh interrogation policies, used during the Bush administration. But underlying all the charges and counter-charges is a larger question: Can Congress genuinely exercise  its authority if the intelligence agencies can classify, and so control, the committee’s oversight efforts?

The CIA has blocked the release of a powerful report from a duly constituted congressional committee, keeping it under “review” for 16 months. CIA officials claim the report contains many inaccuracies. Although President Barack Obama said Wednesday that he was “absolutely committed” to declassifying the report, he was vague on when he would do so.

The CIA reports to the president. Congress can exercise authority, however, because it controls the budget and it has responsibility to oversee  the intelligence agencies. Inevitably, those roles come into conflict as the Senate attempts to exert control over a powerful secret agency of the executive branch.

This power struggle burst into public view during the Church Committee hearings of the  mid-1970s. The Senate hearings stunned the nation with revelations about CIA assassination plots and illegal activities. The result was the creation of congressional committees designed to give the lawmakers greater control over intelligence.