Rubuta ci gaba don wannan sakin layi - Gwamnan Buenos Aires Juan Manuel de Rosas ya yi amfani da karuwar rinjaye a kan sauran ƙasar a lokacin gwamnatinsa na 1835-1852 kuma ya yi tsayayya da tayar da hankali na Unitarian da yawa, amma a ƙarshe an ci shi a 1852
rundunar Sojojin da Gwamna Justo José de Urquiza ya tattara, wanda ya zargi Rosas da rashin bin ka'idodin Yarjejeniyar Tarayya don Tsarin Mulki na Kasa. A cikin 1853, an zartar da Tsarin Mulki na Tarayya (Kundin Tsarin Mulki na Argentina na yanzu, ta hanyar gyare-gyare) kuma an zabi Urquiza a matsayin Shugaban Tarayyar Argentina. Duk da haka, bayan yakin Caseros na 1852, lardin Buenos Aires ya rabu da Tarayyar. A cikin 1859, bayan Yaƙin Cepeda Jihar Buenos Aires ta sake shiga Tarayyar, kodayake an ba ta haƙƙin yin wasu gyare-gyare ga Kundin Tsarin Mulki. A ƙarshe, bayan Yaƙin Pavón na 1861, Buenos Aires ya karɓi ikon Tarayyar.