Historians seem to have a hard time coming up with a definition of Fascism that they can agree on. My suspicion is that a large part of the problem is that many of them come to the table with their mind already made up as to what they expect to find and are just trying to line up enough facts to superficially justify that conclusion and to hell with any inconvenient facts.
One of the more annoying symptoms of this inability to define Fascism in an objective and historically accurate manner is the chorus from the Left in America today that Conservatives and Republicans are somehow Fascists with a political ideology related in some way to that of real Fascists like Adolph Hitler and Benito Mussolini.
As is often the case, especially when dealing with those on the Left, the truth is often just exactly the opposite. Modern day Democrats have far more in common with classical forms of Fascism than do those depicted as being on the right in America.