Some argue that if an agent intentionally participates in collective wrongdoing, that agent bears responsibility for contributing actions performed by other members of the agent’s collective. Some of these intention-state theorists distribute co-responsibility to group members by appeal to participatory intentions alone, while others require participants to instantiate additional beliefs or perform additional actions. I argue that prominent intention-state theories of co-responsibility fail to provide a compelling rationale for why participation in collective wrongdoing merits responsibility not only for one’s own (...) actions but the contributing actions of others as well. I propose that authorization agreements provide us with a suitable rationale. Authorization may be expressly given, as when one person signs a document authorizing another to advance her aims. Or, authorization may be tacitly or implicitly given by participating in and sufficiently contributing to a common plan. If a person authorizes an agent to act, it is right to blame the authorizer for what the agent does on the authorizer’s behalf. An authorization theory justifies the distribution of co-responsibility by appeal to the morally transformative power of agreement, thereby providing a compelling rationale for why a person may be to blame for contributing actions performed by other agents. (shrink)