We're entitled to ask. Ever since 9/11--indeed, even before--Pakistan's military and intelligence services have played a high-stakes double game. They've supported American efforts to kill and capture Al Qaeda fighters, and they have been lavished with billions of American dollars in return. At the same time, elements of those same military and intelligence services, particularly those inside Inter-Service Intelligence, or the I.S.I., have provided support for America's enemies, namely the Taliban and its lethal off-shoot, the Haqqani network. American officials are fully aware of the double-game, and to say it frustrates them would be an understatement. For a decade, Pakistan's role has been one of the great unmovable paradoxes of America's war.