Cordon Sanitaire

French in origin, meaning "sanitary cordon," the term entered formal use in the early 19th century. One of its earliest documented applications was when Paris dispatched 30,000 soldiers to seal the border with Spain and halt an 1820 yellow fever outbreak. In 1869, Adrien Proust (father of novelist Marcel Proust) proposed an international cordon sanitaire to contain cholera spreading from Asia. The political usage — excluding an ideological party or movement from coalitions — emerged in European parliamentary discourse in the 20th century.