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). …

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. …

Al Qaeda hasn’t conducted a successful attack in the West since the bombings on London’s transportation system on July 7, 2005, and of course, the group hasn’t succeeded in attacking the United States for more than a decade.