What is "heckler's veto"

n. Limiting an individual's expression by heckling.

A heckler's veto occurs when an acting party's right to freedom of speech is curtailed or restricted by the government in order to prevent a reacting party's behavior. The common example is the termination of a speech or demonstration in the interest of maintaining the public peace based on the anticipated negative reaction of someone opposed to that speech or demonstration. The term was coined by University of Chicago professor of law Harry Kalven.

In common parlance, the term is used to describe situations where hecklers or demonstrators silence a speaker without intervention of the law.