In June 1935, Basso became brigadier general and in 1936 he was appointed commander of the Royal School of Application of the Artillery and Engineers Branches, until 1938.

[1][2] From 6 November 1940, having been promoted to lieutenant general, he was appointed commander of the XIII Army Corps in Sardinia, with headquarters in Cagliari, where he worked to improve coastal defenses.

[3] When the Armistice of Cassibile was announced, on 8 September 1943, 23,000 German troops under General Fridolin von Senger und Etterlin were also present in Sardinia.

Despite having received explicit orders from Comando Supremo to attack and destroy all German troops present in the island, Basso negotiated with General Carl Hans Lungershausen, commander of the 90th Panzergrenadier Division, their peaceful evacuation towards Corsica, which was accomplished by 18 September with only minor clashes near Oristano and La Maddalena.

From 1 November 1943 Basso was transferred by the Italian Co-belligerent Army to Naples, as commander of the Campania Military Region, but in October 1944 he was dismissed and arrested under charges of failure to execute orders, due to his behavior in Sardinia in September 1943.