Without Restraint

Steve Clemons sums up the meaning of the stonewalling on the request for relevant documents by the Senate Foreign Relations Committee:

The Senate Foreign Relations Committee will not get the much-wanted National Security Agency intercepts in which John Bolton expressed so much interest during his tenure as Under Secretary of State for International Security and Arms Control. Under Secretaries with questionable intentions can get the transcripts -- but Senators with Constitutional oversight responsibilities seemingly cannot.

In short, John Bolton was able to access this highly sensitive material for who knows what purpose--undermining the Secretary of State or spying on colleagues. But United States Senators cannot view the same material for the purpose of performing their oversight duties.
Just as John Bolton sought to act in defiance of the legitimate restraints of State Department protocol or even actual fact, the Bush administration is now seeking to act unilaterally without regard for the legitimate restraint of congressional oversight.