Nationalism was originally a liberal ideology. Unfortunately, because the positions of liberalism seem to be essentially random, they are now anti-nationalist. It's like the political equivalent of Brownian motion.
So ironically, yes, more 1820s era liberalism would help things.
There are some differences. Tribes tend to be relatively small. And for most times before 1800, people were much less averse to being ruled by people of different cultures, languages and ethnicities.
Nationalism was originally a liberal ideology. Unfortunately, because the positions of liberalism seem to be essentially random, they are now anti-nationalist. It's like the political equivalent of Brownian motion.
So ironically, yes, more 1820s era liberalism would help things.
I'm pretty sure Nationalism is just a new label for the default state of humanity for thousands of years: "Hurray for my tribe!"
There are some differences. Tribes tend to be relatively small. And for most times before 1800, people were much less averse to being ruled by people of different cultures, languages and ethnicities.
A nation is just a larger tribe. The nation of Japan is just a tribe the size of the whole archipelago.