It's true that leaders have different styles of command and that anyone assuming the QB role is, at least, in the role of leadership. That role, however, doesn't guarantee that the person holding it is a leader. Leaders have followers and influence and inspire greater effort and results in those who look to them for guidance.
For the past several weeks, Oakland's starting QB, Jason Campbell and All-Pro DT, Richard Seymour, have been organizing team workouts [in lieu of OTAs the lockout precludes] that start next Monday in the Atlanta, GA area.
For all my doubts about Campbell's leadership, Jason is now acting as a leader. If his teammates show up for these workouts and Jason conducts them with authority - while at the same time gaining more influence with the Raiders, then I'll concede that he really may be a bona fide Leader of the Oakland Raiders.