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. Additionally, the constitution established a new political system with a directly elected presidency. The bicameral General Assembly remained the country's legislature, but it was modified through the implementation of midterms elections and a reform of the Senate, whose members would now be elected by the municipal councils for a six-year term with a third of the Senate being up to re-election every two years.

In addition to political reforms, the Radical Constitution codified the abolition of slavery and 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.