Sáenz Peña Law
The Sáenz Peña Law (in Spanish, Ley Sáenz Peña) was Law 1887 of Argentina, sanctioned by the National Congress on 10 February 1912, which established the universal, secret and mandatory male suffrage though the creation of an electoral list (Padrón Electoral). It was approved during the presidency of Roque Sáenz Peña, main supporter of the law.
The right to vote for females was not covered by this law; it was only granted to them in 1947, during the first presidency of Juan Perón. The "universal" scope of the law included only native and naturalized men, therefore excluding not only women, but working class males who were non-citizen immigrants, a very significant portion of the population by then (for example, most of the population in Buenos Aires City at the time was not Argentine).
The original law is currently still in force, but it has been amended to allow women to vote.
Origin and consequences 
Sáenz Peña made his intentions about the voting system public during his first speech before the National Congress, in 1910. Interior Minister Indalecio Gómez projected a reform which left the compilation of the electoral list in the hands of the War Ministry (males over 18 were recorded when called for conscription), while the Judicial Branch was put in charge of dictating who would organize the elections and who would be allowed to vote. This deprived the Executive Branch of its former ability to write and manipulate the electoral list.
The conservative sectors, which had stayed in power for decades through dubious and fraudulent elections, could not consolidate a political party without popular support. Hipólito Yrigoyen, the candidate of the Radical Civic Union (Unión Cívica Radical, UCR) won the first presidential elections that followed the new law by a considerable advantage, and the UCR became the most powerful political force.
As a consequence of the law, all political parties had to reorganize themselves, revising their regulations, creating electoral platforms, opening local seats and periodically gathering in assemblies.
- (Spanish) Sucesos Históricos Argentinos.