Calling someone a "nationalist" is a very serious indictment. How well does "国家主義" translate as "nationalism"?
For example, is this sentence so extreme as to imply something like:
"田中さんは国家主義のある人です。"
"Mr. Tanaka wants to re-build the Imperial Japanese Empire."?
What about the difference between 国家主義 and ナショナリズム? The latter is not easily said nor "spelled" in Japanese. What is the difference between the two?
Even for me (as native Japanese), it's very difficult question. But I also find this kind of interesting, so I will try to answer your question.
In regular conversation, we (at least I) don't mind if you translate "国家主義 = nationalism".
Regarding of Wikipedia, 国家主義 considers the country (or the government) is the first in everything, but ナショナリズム is the word for activities of concert, freedom, and departure...etc.
Wikipedia binds the 国家主義 page to the statism page, not the nationalism page.
It's my understanding that 国家主義 (statism) is part of nationalism.
If you have another opinion, you should post your answer. @Nothingatall was just trying to help... 😢
The root of this answer lies in the word "nation," which has several translations into Japanese. When you look up "nation" in a J-E dictionary, several words come up: 国家 (state), 国民 (citizen[s]), 民族 (slightly outdated translation: ethnic group, e.g. "Hebrew nation"). On Wikipedia, "nation" corresponds to 国民. There is no word for "citizen-ism" based on this 国民 because that doesn't really make sense logically.
Statism 国家主義 implies mostly the belief that the state being the supreme force for order, so it's somewhat akin to the "statism" which you hear libertarians and separatists complain about. It doesn't have the implication of "nationalism" in the sense of imperialism and supremacism, but it does include criticizing political activities which would subordinate local identities to citizen identity.
The old translation of "nation" is 民族 "ethnic group", and a word exists 民族主義 for "ethnicism" (e.g. Zionism, pan-Slavism), but this was never a major partisan force in Japan so it is not used in a critical sense.
The word "nationalism" as used in a left-critical sense doesn't seem to correspond to anything in the Japanese language, so it is best to use the foreign loan word, ナショナリズム. This is the proper translation of "nationalism" according to Wikipedia etc. Now, whether this foreign loanword actually corresponds to anything a politician actually believes in real life is another question.
How can we be asking whether "国家主義" means "nationalism", when the meaning of nationalism itself is very fluid? You have provided one context sentence to fix your particular meaning of nationalism: "wanting to re-build the Imperial Japanese Empire". But that can surely be described specifically as as "imperialism" and "militarism". Is "nationalism" equivalent to "imperialism" and "militarism"? It is true that in times of large scale political change, we are likely to see "nationalism" and "imperialism" and "militarism" appearing more often (along with several other ism's as well). So there is correlation, but correlation does not imply causation.
We are now living in the age of Globalism, a term that includes a range of phenomena extending from higher ideals such as global cooperation on climate change, global peace, elimination of disease and hunger, all the way down to the race to the bottom in workers wages and working conditions, sweeping of industrial pollution under foreign carpets, and under-utilization of human potential in advanced nations.
We now see Nationalism rising in response to the darker side of Globalism. Maybe, instead of reacting violently against either, we need to find a way to let the better parts of Nationalism and Globalism coexist, while leaving the worst of both behind.
We shouldn't be in any rush to define "国家主義" as something a priori bad. It's one the many natural ～主義 in our social gut which when holistically well balanced keeps us healthy, but when not makes us sick.
Edit: According to Wikipedia, "nationalism can be positive or negative".
Nationalism is a complex, multidimensional concept involving a shared communal identification with one's nation. It is a political ideology oriented towards gaining and maintaining self-governance, or full sovereignty, over a territory of historical significance to the group (such as its homeland). Nationalism therefore holds that a nation should govern itself, free from unwanted outside interference, and is linked to the concept of self-determination. Nationalism is further oriented towards developing and maintaining a national identity based on shared characteristics such as culture, language, race, religion, political goals and/or a belief in a common ancestry. Nationalism therefore seeks to preserve the nation's culture. It often also involves a sense of pride in the nation's achievements, and is closely linked to the concept of patriotism. In these terms, nationalism can be positive or negative.
