On 8 May 1860, amid rising tensions between Conservative party politicians in power and the Liberal opposition on the question of federated state's rights and sovereignty, the caudillo and President of Cauca, General Tomás Cipriano de Mosquera y Arboleda, broke relations with the central government and declared civil war against the Administration of President Mariano Ospina Rodríguez. Nieto followed suit and on 3 July broke relations with the central government, soon Mosquera recruited the help of Nieto to overthrow Ospina from power, and sent Ministers Plenipotentiaries to sign a treaty with Bolívar and Nieto as its President; on 10 September, Nieto signed the "Treaty of Union and Confederation of the States of Bolívar and Cauca" ("Tratado de Unión y Confederación de los Estados de Bolívar y Cauca") creating a provisional government and setting the framework for a new republic called United States of New Granada. The treaty also named Mosquera, Nieto and Obando as the First, Second, and Third Presidential Designate respectively.