The State of Buenos Aires is also…

The State of Buenos Aires is also bolstered by its numerous alliances in the hinterland, including that of Santiago del Estero Province (led by Manuel Taboada), as well as its alliances with powerful Unitarian Party governors in Salta, Corrientes, Tucumán, and San Juan.

The 1858 assassination of San Juan's Federalist governor, Nazario Benavídez, by Unitarians had inflamed tensions between the Confederation and the State of Buenos Aires, as had a free trade agreement between the chief Confederate port (the Port of Rosario) and the Port of Montevideo, which had undermined Buenos Aires trade.

The election of the intransigent Valentín Alsina had further exacerbated disputes.

Open hostilities broke out between Buenos Aires and the Argentine Confederation, led by Urquiza.

After Mitre’s federalist forces lose to Urquiza’s centralist army at Cañada de Cepeda, Santa Fe, on October 23, 1859, Alsina has to resign his post, and shortly after Buenos Aires rejoins the Confederation.

Thus the unity of Argentina is generally secured, although it will be two decades before the centralists complete their victory over the federalists.