Editor's note: Peter Bergen, CNN national security analyst, is the author of "Manhunt: The Ten-Year Search for bin Laden, From 9/11 to Abbottabad."
By Peter Bergen, CNN National Security Analyst
The news that Abu Yahya al-Libi, the No.2 leader of al Qaeda, is now confirmed to have been killedin a CIA drone strike in Pakistan's tribal region along the border with Afghanistan further underlines that the terrorist group that launched the 9/11 attacks is now more or less out of business.
Under President Barack Obama, CIA drone strikes have killed 15 of the most important players in al Qaeda, according to a count maintained by the New America Foundation (a nonpartisan think tank where I am a director).
Similarly, President George W. Bush also authorized drone strikes that killed 16 important al Qaeda operatives in Pakistan while he was in office.
As a result, according to senior U.S. counterterrorism officials, there now remains only one leader of any consequence in al Qaeda and that is Ayman al-Zawahiri, the tetchy Egyptian surgeon who became the head of the group following the death of its founder, Osama bin Laden, in a U.S. Navy SEAL raid in Pakistan in May 2011.