Is this constitutional ?
The NYT reports that the SSCI is negotiating with the CIA and NSA about what it can tell the American people.

"In early June, the agency [CIA] had approved for release only about half of the document, Mr. Roberts said last week, and relented only after long negotiations with the committee staff."

Why is a committee of the US Senate negotiating with an agency of the executive branch about what it can write ? I thought that according to the US constitution the Senate was regulated only by itself. I can see the CIA pleading with the SSCI to not reveal sources and methods but what is this "long negotiations" nonsense ?