In 1940, De Bono commanded a southern defense corps headquartered in Sicily and was opposed to the Italian entry into World War II.
But he kept a low profile and, in 1942, he was appointed Minister of State.

On 24 and 25 July 1943, De Bono was one of the members of the Fascist Grand Council who voted to oust Benito Mussolini when Dino Grandi, in collaboration with Pietro Badoglio and King Victor Emmanuel III, put a no-confidence motion to the vote of the Grand Council of Fascism.
That led to the dictator's downfall, arrest, and imprisonment.

Later in 1943, Mussolini was rescued during the Gran Sasso raid and returned to power by Nazi Germany.
 He was set up in Northern Italy by the Germans as the "Duce of the Nation" of a new Italian Social Republic (Repubblica Sociale Italiana, or RSI).
 Upon his return to power, Mussolini had De Bono and others who voted against him arrested.
He then had Alessandro Pavolini try them for treason at Verona in what became known as the "Verona trial".
De Bono was convicted in a show trial.

On 11 January 1944, the 77-year-old De Bono was executed by firing squad at Verona.
He was shot along with Galeazzo Ciano, Luciano Gottardi, Giovanni Marinelli and Carlo Pareschi.
Ciano was the Italian Minister of Foreign Affairs and Mussolini's son-in-law.
Gottardi was the former president of the Fascist Confederation of Industrial workers.
 Marinelli was the former chief of the Fascist militia and Pareschi was the former Agriculture Minister.
The only person on trial who escaped from capital punishment was Tullio Cianetti, the Minister of Corporations.
Cianetti was sentenced to 30 years imprisonment by the RSI judges.
In 1940, De Bono commanded a southern defense corps headquartered in Sicily and was opposed to the Italian entry into World War II. But he kept a low profile and, in 1942, he was appointed Minister of State.
On 24 and 25 July 1943, De Bono was one of the members of the Fascist Grand Council who voted to oust Benito Mussolini when Dino Grandi, in collaboration with Pietro Badoglio and King Victor Emmanuel III, put a no-confidence motion to the vote of the Grand Council of Fascism. That led to the dictator's downfall, arrest, and imprisonment.
Later in 1943, Mussolini was rescued during the Gran Sasso raid and returned to power by Nazi Germany.  He was set up in Northern Italy by the Germans as the "Duce of the Nation" of a new Italian Social Republic (Repubblica Sociale Italiana, or RSI).  Upon his return to power, Mussolini had De Bono and others who voted against him arrested. He then had Alessandro Pavolini try them for treason at Verona in what became known as the "Verona trial". De Bono was convicted in a show trial.
On 11 January 1944, the 77-year-old De Bono was executed by firing squad at Verona. He was shot along with Galeazzo Ciano, Luciano Gottardi, Giovanni Marinelli and Carlo Pareschi. Ciano was the Italian Minister of Foreign Affairs and Mussolini's son-in-law. Gottardi was the former president of the Fascist Confederation of Industrial workers.  Marinelli was the former chief of the Fascist militia and Pareschi was the former Agriculture Minister. The only person on trial who escaped from capital punishment was Tullio Cianetti, the Minister of Corporations. Cianetti was sentenced to 30 years imprisonment by the RSI judges.
Emilio De Bono