The governor of Buenos Aires Province (Juan Manuel de Rosas during most of the period) managed foreign relations during this time.

1/3) of the Viceroyalty of the Río de la Plata, a colony of Spain which also included present-day Bolivia, Uruguay, part of Chile and Peru and most of Paraguay.

[3]In 1828, after Argentine forces returned to Buenos Aires from the war, federalist governor Manuel Dorrego was overthrown and executed by Juan Lavalle, of the Unitarian Party.

The latter began a campaign against all federals, supported by José María Paz in Córdoba, who deposed Juan Bautista Bustos and took similar measures.

He allied with Estanislao López, caudillo and ruler of Santa Fe Province, and they defeated Lavalle at the Battle of Márquez Bridge in April 1829.

[4] When Rosas entered the city of Buenos Aires in November of that year, he was hailed both as a victorious military leader and as the head of the Federalists.

Despite being absent, the political influence of Rosas in Buenos Aires was still strong, and his wife Encarnación Ezcurra was in charge of keeping good relations with the people of the city.

The legislature finally gave up the trial, and a month later ousted Balcarce and replaced him with Juan José Viamonte, a former supporter of unitarians.

Still, the social unrest led many people to believe that only Rosas could secure order and that Viamonte or Manuel Vicente Maza, who had been appointed governor in 1834 as a compromise, would be unable to do so.

The murder in Córdoba in February of 1835 of Facundo Quiroga, a federalist mediator who Maza had sent to a dispute between provinces, increased this belief, so the legislature appointed Rosas governor later in the year, with the sum of public power.

The diplomat Manuel Moreno channeled the protests of the British merchants in Buenos Aires who were impacted by the blockade; this added to French doubts about maintaining a conflict that they had expected to be quite short.

Britain and France joined forces with Rivera, captured the Argentine navy, and began a new naval blockade against Buenos Aires.

The Argentine army resisted the invasion of the river at several points along the Paraná (most notably during the battle of Vuelta de Obligado), but could not stop them.

[10] Justo José de Urquiza, governor of Entre Ríos, had supported Rosas so far, but the ranchers of his province had an expanding economy and wanted to have a local customs, able to engage in commerce with other countries directly.

Urquiza made a pronunciamiento, resuming the rights of Entre Ríos to commerce and negotiations with other countries, instead of delegating such powers to Buenos Aires.

Urquiza's ambition to reduce the national centralism of Buenos Aires and promote a higher federalization of the country generated conflicts with the unitarians.

[14] In 1857, Mitre and other politicians in Buenos Aires considered making the secession a definitive one, renaming the state to the "Republic of the Río de la Plata".

Buenos Aires would call a Constituent Assembly, to accept the National Constitution or requesting amendments, and rejoin the Confederation.