So, I personally don't take all of this Trump Mussolini retweet stuff too seriously. These assholes at Gawker are professional smear merchants, and the quote in question isn't even original to Mussolini.
Here's Pareene at Gawker, at Memeorandum, "How We Fooled Donald Trump Into Retweeting Benito Mussolini."
Everyone's picked up on this story, at the New York Times, for example, "Donald Trump Retweets Post With Quote From Mussolini."
More at Memeorandum.
And scroll through 20 Committee's feed for a while. That "Mussolini quote" apparently preceded the dictator's time in power:
This is the source of the "Mussolini quote": the original, scrawled on a house in June 1918, during the Piave battle pic.twitter.com/yY3zWKdanC— John Schindler (@20committee) February 28, 2016