What did the CIA hide from Congress?

Ambers opens:

Because the executive branch retains a stranglehold on regulations about the disclosure of classified information, there are very few ways for member of Congress who learn about objectionable, classified programs to reveal their discomfort. They can write a classified letter. They can risk prosecution by revealing the information publicly. Or they can do what a gaggle of House Democrats did yesterday: band together, suggest that the CIA misled them about a specific program, and wait for journalists to uncover the details.

He then goes off on a speculation spree. So basically, stay tuned...