‘Mussolini thought the Italians needed to be hardened, and he launched what he called an anti-bourgeois campaign. And among the things he banned, or tried to ban, anyway, was people shouldn’t shake hands, they should give the Roman salute, you know, raising their arm and their hand up in the air. […]
[A] man named Achille Starace, was kind of his circus master, who kept coming up with these ideas of rituals, mass rituals and other kinds of rites that he thought would make the Italians ever more devoted to their duce, which is the kind of Latiny term of leader that the Italians used to refer to Mussolini.
In fact, Mussolini required being referred to as DUCE, D-U-C-E, it’s spelled, and it had to be written in capitals in the newspapers by the 1930s. It couldn’t just be written in the normal way.’
– Kertzer, D. (April 24, 2015) ‘Pope And Mussolini’ Tells The ‘Secret History’ Of Fascism And The Church. NPR.
 duce; ‘leader’ from Latin duco, meaning ‘I lead’. E.g. Il DUCE ha sempre ragione; ‘the leader is always right’.