on 11 June 1847, one of the last cardinal deacons in deacon's orders, he was chosen by Pius IX to preside over the council of state entrusted with the drafting of a constitution for the Papal States.

On 10 March 1848, Antonelli became premier of the first constitutional ministry of Pius IX. Upon the collapse of his cabinet when liberals resigned in protest against the papal public refusal to participate in a war of national