Mamerto Urriolagoitía Harriague (Spanish pronunciation: [maˈmeɾto wrjolaˈɣojtja aˈrjaɣe] ⓘ; 5 December 1895 – 4 June 1974) was a Bolivian lawyer and politician who was the 43rd president of Bolivia, from 1949 to 1951.

He is considered the last constitutional president of the largely oligarchic social and political order that reigned in the country until the advent of the 1952 Bolivian National Revolution.

[2][7][1] The Bolivian Civil War of 1949 broke out following a massacre at Siglo XX mine on 29 May after miners kidnapped and killed several government authorities.

[citation needed] He crushed a number of coup d'état attempts[9] In 1950, he issued decrees, first to make opposition parties illegal, then to outlaw unions.

[12][8] He instituted curfews, shut down newspapers including El proletario,[8] and branded the MNR as communists in discussions with American President Harry Truman in hopes of gaining his support.

[13] Opponents were thrown in prison or killed;[8] opposition leaders including Juan Lechín, Guillermo Lora, José Fellman, and Óscar Únzaga fled the country and remained in exile.

[5] The cost of living, which had been mounting for years, continued to rise,[8] worsened by Urriolagoitía's decision to freeze the salaries of laborers.