The Jacobin Club was a radical society that existed during the French Revolution and the subsequent Reign of Terror. The club had a high entrance fee for members and thus was mostly composed of wealthy bourgeoisie rather than the working classes and peasants. Despite this, the Jacobin leaders were practical and often were forced to make concessions to the working class sans-culottes in order to maintain their power base. The most influential Jacobin leader was Robespierre and under his rule, the Jacobins became the dominant power in revolutionary France for several years. Robespierre was later executed by the other members of the club in the Thermidorian Reaction. The word Jacobin is used today to describe an extreme radical willing to kill his opponents.
The organization also acted as the namesake for the New York magazine of the same name, which as implied by the title dealt with left-wing issues.