Until 1865 the prevailing political idea was fusion (fusión), meaning unity among Uruguayans, the putting aside of the colors and banners that divided them in the past. This idea inspired the administrations of Juan Francisco Giró (1852-53), Gabriel Pereira (1856-60), and Bernardo Berro (1860-64). Hatred and rivalry flared up, however, preventing harmony. Giró was forced to resign. Pereira suppressed almost six coup attempts, and Berro, the last Blanco president until 1958, confronted a revolution led by Colorado Venancio Flores, who took power with the support of Brazil and Buenos Aires. However, General Flores, who had been commanding the armed forces instead of governing the country since that March, was assassinated in Montevideo in 1868, on the same day that Berro was assassinated.

During the period preceding the Great War, the long conflict between church and state also began. It involved Freemasons in government circles and resulted in the expulsion of the Jesuits in 1859 (they were allowed to return in 1865) and the secularization of cemeteries in 1861. Until then the church had almost exclusive control over the cemeteries.

The constitutional government of General Lorenzo Batlle y Grau (1868-72) was forced to suppress an insurrection led by the National Party. After two years of struggle, a peace agreement was signed in 1872 that gave the Blancos a share in the emoluments and functions of government, through control of four of the country's departments. This establishment of the policy of coparticipation (coparticipación) represented the search for a new formula of compromise, based on the coexistence of the party in power and the party in opposition.

A permanent break in the cycle of near anarchy and repression was anticipated when José Ellauri (1872-75) was elected president. His administration was characterized by the predominance of university men over caudillos. A number of them, known as the "Girondists of 73" were sent to the General Assembly. Unfortunately, however, the ensuing economic crisis and the weakness of civil power paved the way for a period of militarism.

Data as of December 1990