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“Bin Laden always looked up to him,” said terrorism expert Bruce Hoffman of Georgetown University.
Al-Zawahri's path went from Cairo clinic to top of al-Qaida →
"Their objective is to wantonly attack the U.S. because they see the U.S. as their main enemy," Mr. Hoffman said. "Also, I think it's designed to embarrass the Taliban as well. ISIS attempted to move in and establish a base in Afghanistan to compete with the Taliban. Their ideologies are pretty much the same. It's more of a power struggle than an ideological or religious one."
