Governor Juan Manuel de Rosas had been elected to his position in 1835, after which he eliminated his most prominent opponents— especially the Unitarians, but also his fellow Federalists. Rosas drew political support largely from the army and the cattle ranchers, whose interests were well served by his government's economic focus on agricultural exports. However, Rosas' conflict with France in the War of the Confederation changed the economic and social conditions in Buenos Aires Province when the French navy blockaded the Río de la Plata beginning in 1838.