He was the force behind "La Regeneración" (Regeneration) movement of 1884 and the new Constitution for Colombia of 1886. The Regeneration program advanced by Núñez opposed most liberal reforms established in the Constitution of Rionegro, and its victory changed the country from a decentralized federal system to a centralized system with a strong central presidency. Opposing the conservative and centralist tendencies in Núñez proposal, liberal leaders issued yet another civil war in 1884 and 1885. The conservative forces in favor of president Núñez finally surrendered the liberal troops in 1885, which led to Núñez' famous proclamation: "Sirs, the Constitution of 1863 is no more." Following this military victory, on September 10, 1885, Núñez summoned two representatives from each of the sovereign states to initiate the Constituent Assembly, which was installed on November 11 of the same year.