the estimable Col. Tom Kratman makes an interesting differentiation between Marxisms and Fascisms:
http://voxday.blogspot.com/2015/10/you-invited-them-you-deal-with-them.html#comment-57
"WRT Hitler being left. No he wasn't. He was of the extreme, but of the
extreme right, not the extreme left. Tactically and technically the
approach can be, and often is, similar for both, and the goal,
perfection of man, is the same, but the underlying philosophy - nature
v. nurture - are quite different, which will drive them to great
operational and strategic differences."
http://voxday.blogspot.com/2015/10/you-invited-them-you-deal-with-them.html#comment-64
"That core difference, rather the core articulable difference, between
right and left concerns the nature of man, malleable / perfectible by
breeding (with the variant of "already perfect or, at least, superior so
must be defended from downbreeding), or by environment ..."
i actually agree with Tom vis-a-vis the Nature v Nurture philosophical axis being a useful dividing line between Fascisms and Marxisms. unfortunately for Tom, this is only one philosophical axis upon which they diverge from each other. there are at least two more ( Nationalism v Internationalism and exaltation of Emotionalism v [ purported ] Rationality ).
the problem is that *none* of these philosophical axes are intrinsically of either the Left or the Right.
worse, the criteria he has chosen, the "perfectibility of man" CANNOT be 'of the Right'.
the Right ( especially Christians ), believe that Man CANNOT be 'perfected' while present on the material and corrupt Earth. to assert that Man is perfectible without Christ is, within the Christological worldview, explicitly Satanic.
for a Roman Catholic to assent to the assertion that mortal Man is perfectible in the Here-and-Now is to stipulate to a philosophical position which is explicitly at odds with his professed religious principles.
the actual Right / Left divide here lies between the positions of Corrupt and Imperfect Man v. the Perfectible Man.