From a comment I left at The Politically Incorrect Australian
Nationalism was powerfully motivating, but only for about one generation after the mass apostasy from Christianity began (this happened at different times in different countries).
As of now, nationalism is ineffectual; and it is a waste of time - and diversion from the real problem - to pursue it.
Nationalism is just one of a long series of failed attempts to motivate people after they have abandoned religion - this universal secular demotivation can be seen in the voluntary subfertility (subfertility in spite of material abundance) among all secular Western societies.
The only groups in modern society with above replacement fertility are from among the religious, and only among the seriously religious (these seem to be only among Christians, Muslims and Jews - Eastern religions don't seem to work - certainly not outside of the East).
To be clearer, I think a large majority of people in The West are in favour of not being replaced by assorted immigrants; but they are (like all established secular populations) too morally incoherent and hence insufficiently motivated to anything about it - when doing something involves the slightest risk or disadvantage.
This affects everything, which is why totalitarianism is established and increasing its grip - almost nobody will say no, because almost nobody can believe-in any coherent alternative.
No belief, no motivation: Demotivation unto death, and beyond: Terminal demotivation...