In a previously undisclosed letter, John Brennan, the White House counterterrorism advisor, pushes back on complaints on Capitol Hill that the Obama administration has not been cooperative with Congress over the Nov. 5 massacre at Fort Hood, Texas.

"I do not believe this is a fair or accurate assessment," Brennan writes."Starting from the first moments after this tragedy, the President directed us to keep Congress appropriately informed."

Brennan goes on to detail the various briefings members of the administration have given to congressional leaders, committee chairs, and staffers, and promises that  more information from the Pentagon, the Office of the Director of National Intelligence, and the FBI is forthcoming.

The letter, addressed to Joseph Lieberman and Susan Collins, is dated Jan. 27 and was exclusively obtained by The Cable. It is ostensibly a response to a Dec. 3 request by the two senators, who cochair the Committee on Homeland Security and Government Affairs, for certain unspecified documents.

To the Army's evident discomfort, Lieberman has suggested repeatedly that the Fort Hood shooting was terrorism, not a random act by a mentally disturbed individual, and vowed to use the committee to fully investigate the incident. The shooter, Army Maj. Nidal Hasan, has been linked to Anwar al-Awlaqi -- the radical Yemeni-American cleric who has since become a top "kill or capture" target for U.S. intelligence agencies and Special Forces teams operating in Yemen -- but Hasan showed signs of deep emotional instability before his Nov. 5 attack.

In his letter, Brennan first refers to the massacre as a "tragedy," but he seems to hedge his language here:

The President has a solemn responsibility to protect  this nation from future acts of terrorism. In sharing what we have learned about what happened at Fort Hood, he is confident that we can help prevent such senseless acts of violence in the future."

So which is it? Terrorism or a senseless act of violence?