In William Golding's Lord of the Flies, Ralph and Jack embody two opposed models of authority, and the contrast between them drives the novel's argument about civilisation and savagery. Ralph governs by consent and reason; Jack rules by fear and force.
Source of authority. Ralph's authority is democratic and legitimate. He is elected chief by the assembly, and his power rests on the conch shell, the agreed symbol of order and the right to speak. Jack's authority, by contrast, is self-appointed and coercive. He seizes leadership by breaking away, forming his own tribe, and dominating the boys through intimidation. Where Ralph is chosen, Jack takes.
Aims of leadership. Ralph's chief concern is rescue and the common good. He insists on keeping the signal fire burning, building shelters and holding orderly meetings, that is, on the long-term welfare of the group. Jack's concern is hunting, meat and immediate gratification. He offers the boys excitement, feasts and the thrill of the kill rather than the discipline of survival. Ralph appeals to their better selves; Jack appeals to their appetites and fears.
Method of rule. Ralph tries to persuade and to share responsibility; he consults Piggy, values fair debate, and respects the right of each boy to speak while holding the conch. Jack relies on terror. He beats and tortures his followers, uses the myth of the "beast" to control them, paints his face to shed shame, and has dissenters punished. His rule culminates in murder, the killing of Simon and Piggy, and the hunt to destroy Ralph.
Symbolic contrast. Ralph is aligned with the conch, the fire-for-rescue and the rule of law; Jack is aligned with the spear, the war-paint and the severed pig's head. When the conch is shattered along with Piggy's death, Ralph's civilised authority collapses and Jack's savage power triumphs, at least until the naval officer arrives.
Conclusion. The difference between the two leaders is finally the difference between civilisation and barbarism. Ralph's fragile, rational authority represents order, conscience and the group's future; Jack's brutal charisma represents the dark, anarchic instincts that Golding believes lie beneath the human surface.