John Brennan is the senior counterterrorism adviser to President Barack Obama, who also advises on relations between the White House and United States intelligence community. He was a career Central Intelligence Agency officer, and was under consideration for appointment as Director of National Intelligence or Director of the Central Intelligence Agency (DCIA). During the campaign, he had been Obama's adviser on intelligence matters. The administration faced opposition from Senators based on Brennan's involvement with the controversial interrogation of terrorist suspects, and chose to put him in a position where Senate confirmation was not required. He reports to the Assistant to the President for National Security Affairs, originally James L. Jones and now Thomas Donilon, working with the National Security Council.
His role has similarities to that held by Richard Clarke, but he has maintained a lower profile. W. Patrick Lang and Philip Giraldi have spoken disparagingly of Brennan, saying his primary skills are in behind-the-scenes bureaucratic infighting rather than intelligence and counterterrorism. 
According to DCIA Leon Panetta, "John understands how intelligence and policy support one another -- that's a major asset...He is a vital link between the CIA and the NSC." Brennan rejects the pure "hard power" assumption implicit in the term war on terror.
Reporting on Jones' resignation suggested that Brennan was one of the deputies consulted by the President more often than was Jones. 
He gave a speech at the Center for Strategic and International Studies on August 6, entitled "A New Approach for Safeguarding Americans" As far as the situation with al-Qaeda,it has been "seriously damaged and forced to replace many of its top-tier leadership with less experienced and less capable individuals. It is being forced to work harder and harder to raise money, to move its operatives around the world, and to plan attacks. Nevertheless, Al Qaeda has proven to be adaptive and highly resilient and remains the most serious terrorist threat we face as a Nation." He said it had a "safe haven in Pakistan’s Federally Administered Tribal Area (FATA), and networks with local organizations around the world.
By forcing the Taliban out of Afghanistan, al-Qaeda is denied sanctuary there. "In East Africa and the Trans-Sahel region, we are sharing intelligence with partner nations and building the capacity of their security forces to deny al Qaeda safe havens....We are actively working with and through the international banking community to deny resources and funding to the al Qaeda network and the businesses that support them." International law enforcement has been effective.
Daniel Pipes of the Middle East Forum was extremely critical.  describing as summarizing the "administration's present and future policy mistakes...It's a deeply deceptive interpretation intended to confuse non-Muslims and win time for Islamists." Pipes observes that it does not make a hard link between "violent extremism" and Islam; Brennan explained that jihad has multiple interpretations, not all violent. Pipes said this is a disinformation strategy of the Muslim Brotherhood, described in a paper by LTC Joseph C. Myers, U.S. Army, at the Air Command and Staff College.  While Pipes agrees with nuclear weapons in terrorist hands as the greatest step, he describes, policy response to "of three feeble and nearly irrelevant steps: 'leading the effort for a stronger global nonproliferation regime, launching an international effort to secure the world's vulnerable nuclear material …, and hosting a global nuclear summit.'"
Al Qaeda in the Arabian Peninsula
Speaking about the White House review triggered by the Christmas 2009 attempted bombing of a U.S. airliner, as well as security developments in Yemen, he indicated that one of the greatest surprises was that Al-Qaeda in the Arabian Peninsula (APAP) had worldwide objectives. He said "The fact that they had moved forward to try to execute this attack against the homeland I think demonstrated to us -- and this is what the review sort of uncovered -- that we had a strategic sense of sort of where they were going, but we didn't know they had progressed to the point of actually launching individuals here,...nd we have taken that lesson, and so now we're all on top of it." 
Previous intelligence work
He was involved in setting up several interagency counterterrorism groups, such as the Terrorist Threat Integration Center, which were intended to break through the "stovepipes" that may have prevented information sharing that conceivably could have averted or reduced the 9/11 Attack. Testifying to the 9-11 Commission, he spoke of a need for cooperation between intelligence and law enforcement. 
His CIA assignments included Station Chief in Saudi Arabia and Executive Assistant to the Director.
- Glenn Greenwald (25 November 2008), "Exceptional news: John Brennan won't be CIA Director or DNI", Salon.com
- W. Patrick Lang, ed. (January 2010), ""A" Grade?", Sic Semper Tyrannis
- Spencer S. Hsu and Joby Warrick (6 August 2009), "Obama's Battle Against Terrorism To Go Beyond Bombs and Bullets", Washington Post
- Scott Wilson (8 October 2010), "James Jones to step down as national security adviser", Washington Post
- John Brennan (6 August 2009), A New Approach for Safeguarding Americans, White House
- Daniel Pipes (18 August 2009), "Counterterrorism in Obama's Washington", FrontPageMagazine.com
- Douglas Farah, "U.S. Muslim Brotherhood Groups Called "Threat Organization" in DOD Memo", Counterterrorism Blog
- CBS News, 7 January 2010
- John O. Brennan, Director, Terrorist Threat Integration Center on Law Enforcement and the Intelligence Community (14 April 2004), Statement on Law Enforcement and the IC (Intelligence Community_, National Commission on Terrorist Attacks Upon the United States