Riograndense Constitution of 1851 (RRG)

The Constitution of 1851 was adopted on September 16, 1851 by the military government of the Riograndense Republic in the aftermath of its military coup by the members of the Radical Party, replacing the previous 1841 Constitution. The text is also known as the Radical Constitution as was based on liberal ideals of democracy and secularism.

The new constitution was influenced by the French and American revolutions and grounded on the principles of democracy and secularism. The text significantly reduced the power of the Catholic Church by declaring the freedom of belief and ending Catholicism's status as the state religion. The advent of the Second Republic permitted the codification of the abolition of slavery and the adoption of a bill of rights that cataloged fundamental rights such as freedom of assembly, press, property, and speech. With the adoption of the Radical Constitution, the Riograndense Republic entered a period of important reforms that would make it the richest country on the continent, which was in large part due to the progressive ideas inscribed into the text.

Additionally, the constitution established a new political system with a directly elected presidency, as well as the office of the vice presidency. The bicameral General Assembly remained the country's legislature, but it was modified through the implementation of midterms elections and a new electoral system where its members would be elected from local districts. The reformed Senate would therefore be elected directly from a single nationwide constituency. Inspired by the example of the United States, the constitution introduced midterm elections as the length of the term of the members of the Chamber of Deputies was reduced to two years while the length of a senator's term was cut to six, with a third of the Senate up to re-election every two years.

Major reforms

 * 1860: the three senatorial classes are reformed into two classes