File photo dated May 1, 1998 of Oussama Bin Laden, with Ayman al-Zawahiri, his right hand man in Jamkha, Afghanistan. Zawahiri was killed in a counter-terrorism operation carried out by the CIA in the Afghan capital of Kabul on Sunday. Mr Biden said Zawahiri had "carved a trail of murder and violence against American citizens". "Now justice has been delivered and this terrorist leader is no more," he added. Zawahiri took over al-Qaeda after the death of Osama Bin Laden in 2011. He and Bin Laden plotted the 9/11 attacks together and he was one of the US's "most wanted terrorists". Photo by Balkis Press/ABACAPRESS.COM
The US killing of Zawahiri was more retribution than prevention

According to documents obtained from the raid that killed bin Laden, al-Qaida’s 9/11 era leaders have little impact on current operations.

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