After Taliban emir Mullah Mansoor was killed in a U.S. drone strike on May 21, one key question is whether al-Qa`ida leader Ayman al-Zawahiri will pledge allegiance to his successor. When al-Zawahiri pledged allegiance (bay`a) to Mansoor last summer, some observers were puzzled. Instead of laying claim to the title of emir al-mu’minin (commander of the faithful) and directly challenging Abu Bakr al-Baghdadi for leadership of the global jihadist movement, al-Zawahiri exposed himself to ridicule by subordinating himself to a man whose succession to Mullah Omar was opposed initially by significant factions of the Taliban movement. But at a time of rising competition from the Islamic State, al-Zawahiri arguably had little choice. His decision was consistent with strategic maxims that have defined his career, including forging and maintaining alliances to ofset weakness. Nine months later, with the Taliban surging in Afghanistan and al-Qa`ida riding its coattails, his decision appears to be paying dividends, and he is likely to pledge bay`a to Mansoor’s successor, Mullah Haibatullah Akhunzada.