The Prohibition Party (PRO) is a political party in the United States best known for its historic opposition to the sale or consumption of alcoholic beverages. It is the oldest existing third party in the US. The party was an integral part of the temperance movement. While never one of the leading parties in the United States, it was once an important force in the Third Party System during the late 19th and early 20th centuries. It declined dramatically after the repeal of Prohibition in 1933.