If Baitullah Mehsud, the Pakistani Taliban's most dangerous and powerful leader, was indeed killed by a U.S. Predator drone strike earlier this week, the biggest loser of all may be Osama bin Laden's Al Qaeda. For the past eight years, the group had depended on Mehsud, his close allies, and other sympathetic tribals to protect it in South Waziristan after its previous host, Mullah Mohammed Omar, was chased from Afghanistan by American bombs in late 2001. With Mehsud gone, Al Qaeda could be in trouble. "Mehsud's death means the tent sheltering Al Qaeda has collapsed," an Afghan Taliban intelligence officer who had met Mehsud many times tells NEWSWEEK. "Without a doubt he was Al Qaeda's No. 1 guy in Pakistan," adds Mahmood Shah, a retired Pakistani Army brigadier and a former chief of the Federally Administered Tribal Area, or FATA, Mehsud's base.