SPOILERS for LOST.
Jack
Jack’s leadership is defined by two things: his enthusiasm for giving people what they want, and his ability to react in the moment. His choice to take up leadership in the first place comes from other people wanting him to take up leadership against his personal wishes, and people want him to take up leadership because they see him successfully navigate the crisis of a plane crash. These two things end up defining the choices he makes as leader; he’s largely reacting to one crisis after another, and his reactions are based on what would make these specific people in this specific community happy. People need water, so he goes and finds water. Locke wants to push the button, so he helps Locke push the button. Michael wants to find his son, so he helps Michael find his son. Another way of looking at it is that Jack uses the role of leadership to create community, and that means both his problems and solutions come from the people in that community. That sense of reacting creates its own problems and solutions too; Jack’s terrific ability to move in a crisis serves him extremely well when he’s dealing with an area in his expertise, but when he’s faced with a situation he doesn’t fully understand, he’ll pick one easy explanation and commit to it wholeheartedly.
Ben
Ben’s leadership is defined by expressions of power. He chose to become a leader because he was tired of feeling weak, and most of his decisions are based around seizing or flaunting power; much of what he does on a day-to-day level is about survival, but he only has to survive because he took on enemies as grand as he wants to be. Even the fact that he’s serving Jacob only flatters him with an extraordinary amount of power – the same way people can believe in an all-powerful God and that they are important because they have a direct line to him. Backing this up is his particular, peculiar kind of intelligence – he’s able to weave together all the disparate details around him into a coherent picture, and he can use that picture to determine the best next step to take. In his own way, he’s as reactive as Jack, but he’s reacting to the whole picture rather than with pure impulse. For him, it’s not so much a community as it is a system that he’s pushing about at will.
James
James rises to a position of leadership in season four in a manner not too dissimilar from Jack at the start of the show – he happens to be in the right place at the right time with the right kind of competence, confidence, and charisma. It’s there that the similarities end. Admittedly, he’s thrown into a situation that he has a better grasp of than Jack ever did, but he’s also operating from a different set of principles. There’s a point where he criticises Jack for simply reacting, and his leadership is based not on a vague and wish-washy idea of ‘fixing things’, but on a single, quantifiable goal: keep everybody alive and safe. He’s less distracted by the emotions of others – less willing to go along with something just because other people want it, less interested in telling people what they want to hear – and so he has a real knack for solving problems both in the moment and long-term. It’s a visionary leadership, where he has one goal centering him on both micro and macro levels; part of the fun of seasons four and five is watching him essentially juggling a todo list, and he puts his people in positions where they can be the most effective.
Jacob and The Man In Black
If you look at LOST as a mystery, then part of the journey is discovering that Jacob and The Man In Black have been acting out two schemes for longer than the run of the show in season five’s finale. If you look at LOST as an exploration of the nature of leadership, then Jacob and The Man In Black are the apotheosis. James’s goal was clear but nonspecific, which gave him some flexibility in its expression and allowed him to sustain it a long time. The Man In Black has one specific action he’s trying to do (get off the island) while Jacob has a specific action he’s trying to prevent (destruction of the heart of the island). Every action both men are doing is about getting to their particular action (or I suppose maintaining a particular action, in Jacob’s case). They ruthlessly use the people and elements of their systems to advance their specific agendas, using every moment to set something in motion that they think might help later. John Locke never quite manages to achieve a leadership role; the one chance he gets in season three implodes almost immediately, because he’s simply that unstable and directionless. But I like to think that The Man In Black in seasons five and six really does show us what kind of leader John could have been if he’d achieved inner peace.
Hurley
Hurley receiving the mantle of leader is one of the last actions of the show, so we never actually see what kind of leader he is, but we can make a pretty good guess based on what we see in the show, and I think Ben assesses him correctly. Hurley will use the system he has as an expression of the infinite capacity to love within him. Jack made people happy, but Hurley will generate happiness within himself and use the island and the system of it to project that happiness out into the world, just like he did when he built a golf course and got the van working and made everybody lunch. He also has the self-awareness and lack of ego to bring in someone he trusts to compensate for his weaknesses and guide him through tougher decisions.