A rubber stamp, as a political metaphor, refers to a person or institution with considerable de jure power but little de facto power; one that rarely or never disagrees with more powerful organs.

The term itself likely stems from the commonplace practice of subordinate employees or officials being deputized and given the authority to sign the name of their superior or employer. In situations where this superior official's signature may frequently be required for routine paperwork, a literal rubber stamp is used, with a likeness of their hand-written signature. In essence, the term is meant to convey an endorsement without careful thought or personal investment in the outcome, especially since it is usually expected as the stamper's duty to do so. In the situation where a dictator's legislature is a "rubber stamp", the orders they are meant to endorse are formalities they are expected to legitimize, and are usually done to create the superficial appearance of legislative and dictatorial harmony rather than because they have actual power.