Partido Liberal Mexicano
From 1903, Villarreal turned against the dictatorship of Porfirio Díaz. He published a number of liberal magazines and was subsequently imprisoned. After his release he fled to the United States where he joined, the anarchist Mexican Liberal Party (PLM) of Ricardo Flores Magon. At the outbreak of the Mexican Revolution in 1910, he joined the Progressive Constitutionalist Party (PCP) of Francisco Madero, and after Madero's victory in 1911 he was appointed consul in Barcelona.