Nationalism as nations’ right to self determination and self rule is great. And that’s what brought down the old empires. While now empires are rebuilt under anti-nationalist slogans and we are sliding back to multinational behemoths.
Good case why healthy dose of patriotism-nationalism is necessary is Ukraine war.
Orwell seems to describe what you’re defending as patriotism, not nationalism.
Yes, it's sort of desire to take power from bigger multinational structures back to the nation. But at the same time it's defensive from nation's perspective.
Worth bearing in mind when discussion abstract concepts like 'nationalism' and 'nationality' though.
As for „national interests“ and „national security“, you get the same with tribalism.
What nation and nationalism brought to Europe is a series of wars that were as destructive as religious ones, at the time when religious fervor finally died down. And it is still doing more of that.
WW1 was brought by multinational empires. WW2 was brought by SSRS and Nazi (National-socialists). Yugoslavia was an attempt to build multi-national pan-slavic empire as well.
Historically imperialistic multi-national tribes try to build some sort of pseudo-national identity and erase small tribes. Be it SSRS with the new soviet man, Spain trying to incorporate Basques and Catalonians, UK and Scotland and so on.
If you look at 19th century and beginning of 20th century, nations/nationalism brought down the big empires. Austro-Hungary, British and Ottoman empires... Russian empire is still trying to survive but it will follow that way soon.
I find it particularly weird that you list WW2 as not brought by nationalism, given that Nazism is basically an extreme form of ethnic nationalism.