Campioni refused repeated offers to collaborate with the Social Republic. He based his decision on his view that the Social Republic government was illegal and that Italys legitimate government remained the Kingdom of Italy, which controlled the southern part of the country and had switched sides and joined the Allies. As a result of his stance, an Italian Social Republic military tribunal in Parma convicted him of high treason and condemned him to death. The Social Republic offered him a pardon on the condition that he recognize it as Italys legitimate government, but he rejected the pardon and was executed along with "Contrammiraglio" Luigi Mascherpa and others by a firing squad composed of youths aged 17 and 18 in the city square at Parma on 24 May 1944.