To many, the sphinx-like commander of Pakistan's military is the most essential figure in the war against militant extremism in South and West Asia. But that's the problem. Pakistan's military, at once opaque and shadowy, is an institution with a checkered history of abetting Islamist militancy. And Kayani's charges were thrust into the spotlight this May following the U.S. raid on Osama bin Laden's compound in Abbottabad, a suburb of Islamabad and home of one of the country's top military academies. U.S. officials, many of whom had been circumspect about Pakistan's perceived double-game in the past, became far more vocal about Pakistan's failings after it became clear that Bin Laden had been living deep inside Pakistan, in a comfortable home, and not skulking in mountain hideaways along the Af-Pak border. Outgoing U.S. commander Adm. Mike Mullen labeled the powerful Taliban-linked Haqqani network "a veritable arm of the ISI," the Pakistani military's intelligence agency. A steady chorus in Washington now calls for the cutting of billions of dollars in aid to Pakistan's military — a threat Kayani has shrugged off. Following the November slaying of 24 Pakistani soldiers by a NATO air strike — an attack that has been deemed an accident by NATO — relations hit a new low, with Pakistan's civilian leadership promising that "business as usual" with the U.S. was over. However the endgame in neighboring Afghanistan and the greater region shakes out, Kayani, a man many suggest is the most powerful in Pakistan, will be at its heart.