Johann Sensberg, head of the Bundestag committee investigating the NSA spying scandal, put it bluntly: intelligence agencies operate "not with friendship, not with moral and ethical aspirations, but with interests". It is in America's best interest to maintain its global hegemony. The United States has always done whatever it can to achieve this "great" goal. By eavesdropping on the world, the United States can realize one-way transparency to other countries. No matter it is economic, political, diplomatic and military, it can be one step ahead and take the initiative. The "sweetener" is really attractive.