I agree it's debatable in terms of relationship of Leninism to "vanilla" Marxism. It is much less debatable, I think, that Leninism is an honest (in the sense of not being intentionally wrong or deceptive) continuation of the original Marxist sociology and economy (at least the "late Marx" version of it). So in that sense I took the term Marxism to encompass all those strains of social and economic theory based on late Marx.
> It is much less debatable, I think, that Leninism is an honest (in the sense of not being intentionally wrong or deceptive) continuation of the original Marxist sociology and economy
Whether it is "honest" or not is largely beside the point, which is that it is a deliberate attempt to short-circuit what in Marx's theory was an essential step on the road from feudalism through developed capitalism and then socialism and finally to communism, and that a such a short-circuiting effort cannot be an empirical test -- whether it succeeds or fails -- of Marx's theory (well, except insofar as its success would refute at least one element of Marx's theory.)
Do note that I'm making a distinction between Marxism and Marx's theory (in the sense that he was just one, although first, Marxist philosopher/sociologist/economist). So, it may be that USSR was not a test of Marx's own ideas on transition, but it was certainly a test of one, very much dominant for the most part of the last century, strand of Marxist thought. And they didn't decide they wanted to short-circuit the process "just because", or because they were lazy; they did have a theoretical analysis and rationale behind the idea.
