The Joint Chiefs are the president's "tech support," in matters military. They are not vested with command authority, but serve as the CinC's primary advisors on propriety and impropriety of the military's uses as well as it's capabilities and limitations. In that sense they do have a prinicple role in the formulation of policy, but their actions are doctrinally, nothing more than recommendations that need the approval or disapproval of the president in matters of execution, and congress when it comes to appropriations.
Right, their job is to advise, so whats the point of the article?