Although leaders are normally seen as one individual that runs a large group, after reading Heifetz article, "leadership in a crisis" I believe leadership should be distributed throughout if the leader is not successful. It takes an extreme amount of experience and knowledge to be able to run a large group of people and be able to function effectively. With more than one person running a group the greater the knowledge and experience there is. The more you know, the greater chance there is for success. Leadership is carrying or guiding a group forward whether if it's within an organization or for a school project. My extension to the definition of leadership is that more than one person can be seen as a leader within a group. As long as the leaders are successful at what they do.
Heifetz, R., Grashow, A., & Linsky, M. (2009). "Leadership in a (permanent) crisis." Harvard Business Review, 87(7), 62-69.