Which legal principle allows a principal to be held liable for the actions of his/her agent even if those actions were unauthorized?

Vicarious liability is the legal principle that holds a principal accountable for the actions of an agent when the agent is acting within the scope of their role, even if the agent's actions were unauthorized or improper. This principle is rooted in the understanding that a principal has a level of control over their agent's actions and thus bears some responsibility for how those actions affect others.

In practice, vicarious liability is often applied in employer-employee relationships, where an employer can be held liable for the negligent acts of an employee if those acts occur during the course of their employment. This doctrine encourages principals to exercise due diligence in selecting and supervising their agents, recognizing that the relationship between the principal and agent inherently involves a delegation of authority and responsibility.

The other concepts mentioned do not encompass the same responsibilities that vicarious liability does. Informed consent refers to the agreement made with knowledge of the risks involved, active negligence involves direct fault in conduct, and countervailing evidence pertains to evidence that contradicts other evidence in a legal context. None of these directly address the issue of liability arising from an agent's unauthorized actions on behalf of a principal.