Why is there a battle between the CIA, Executive and Congress?
The U.S. secret and intelligence agencies have a terrible record of maintaining secrecy. Both the FBI and the CIA had top level communist moles for forty years, so did the State Department. That means many operatives overseas died because of the failed secrecy of the secret and intelligence agencies. Remember, in 1996 I knew Valerie Plame was a CIA employee. Few overseas operatives are, to this day, willing to work for the U.S. Nobody competent could be dumb enough.
That is only half the problem.
The other half of the problem is that Congress is even worse with secret material. For the past forty years every person who had been a Marxist or communist in their younger years, headed straight for a position on the Congressional intelligence committees as soon as they got elected to Congress. Two shocking examples that I personally know of were Phil Burton an open Communist (along with his wife Sala) who was also Democratic Party whip in the House for 10 years. And Ron Dellums with the same background who was in Congress for nearly 30 years. Both actively hated the CIA and yet they sat on nearly every intelligence briefing. Did they keep any important secrets?
I don't know the other people who have been on the intelligence committees, I haven't paid attention, but what I know is enough to make it obvious that an intelligence briefing with Congress is a direct telegram to the people from whom the secret is being kept.
That is mostly why the CIA and the Executive hate to brief Congress about anything.
While we are at it... Democratic Congresses, more than any other group, caused the intelligence breakdown on 9-11. Congress passed legislation making it illegal for the FBI to cooperate with the CIA. That made 9-11 a certainty according to the 9-11 Commission.