The Power Storyline is one of two story arc tracks available to Loyalist characters. Only Loyalist-aligned player characters have access to these story arcs, although players who role-play their characters as Resistance-aligned but in "deep cover" can betray their mission objectives to Calvin Scott.
Those who are in Power use the law for their own benefit, whether it be to gain power, fame, or glory. If they do help the people of Praetoria, it's only because it happened to fit into their own plans. People who follow the Power path are often praised by the people as heroes while hiding their true agenda from the masses.