 Before we go deeper into the divide between left and right institutionalism, it’s important to note what the two sides agree on and to see where the actual disagreements between the two sides lie. The important point of agreement lies in their mutual focus on institutions or rule-governed practices as the trigger of genuinely egalitarian distributive obligations. Both right and left institutionalists accept that principles of distributive justice only apply or are activated in particular institutional contexts or when people mutually participate in practices that are relevant to distribution. So, both right and left institutionalists would deny that we have obligations of distributive justice to, say, the lost city of Atlantis—should it appear—since Atlanteans have not participated with us in shared institutions or practices. In other words, principles of distributive justice apply to, and are activated by, a basic structure that mostly determines the distributive shares the participants receive. Right and left institutionalists disagree, then, concerning which institutions activate obligations of distributive justice among participants.