I've written often over the past decade about why it is a mistake for those in The West who oppose the Left to put their faith in nationalism.
Another reason I have not mentioned directly is a consequence of the universal corruption affecting all large and powerful Western institutions - their loss of specific functions, and their convergence into the single, global totalitarian bureaucracy of New Left Political Correctness.
The problem is simply that the nation is an institution. So, because it is an institution, the nation is Leftist.
This fact is often missed because the nation is not just an institution; a nation is also (potentially, and to a variable extent) a mystical entity. But it is a mystical entity only insofar as people are able and willing to recognise the reality and importance of mystical entities - which, in the case of modern states, is Hardly At All.
Nationalism was only a strong force in the immediate post-religious generations (from about the middle 19th to 20th centuries) when people were still capable of living by and from mystical beliefs.
But that time is long gone, and mystical nationalism is now far too weak, or non-existent - and what we are left-with is a corrupt, converged national institution, a Leftist national institution.
How can people then realistically hope that nationalism might defeat Leftism? Right-Nationalists are in the position of supporting, trying to build-up and make supreme an institution that solidly and increasingly opposes their goals.
It isn't going to work, is it?
The only genuine possibility, remote and slight though it is; would be a religious revival first, and then (but only then) all kinds of good things become possible.