Here's a good example of what's been wrong with congressional oversight of the intelligence agencies for decades: House Speaker Nancy Pelosi says the CIA did not tell her at a September 2002 briefing (when she was the senior Democrat on the House intelligence committee) that it had used waterboarding on a captured al Qaeda operative; the CIA says it did. And this dispute apparently cannot be settled. From The Washington Post:
Government officials, who spoke on the condition of anonymity to discuss classified briefings, suggested that the record might never be clear as to what Pelosi and [Republican Rep. Porter] Goss were told. One official familiar with the congressional briefings acknowledged the difficulty of establishing exactly what lawmakers were told. Internal CIA memos about the briefings were "not designed to be stenography" but were based on recollections after the fact, the official said. There were no recordings or precise transcripts, he said.
Shouldn't there be better record-keeping? It's pretty absurd that the CIA cannot say what it actually told a legislator during an official briefing.