the most important conflict is class conflict, and my most immediate enemy is the ruling class of my own country
In some situations that might be true but I think it depends. In some cases, the ruling class of your own country might be investing in a military which protects you, while a foreign government might want to invade your country and oppress you. For example, if you were an American Jew in WW2 then surely the US ruling class was a better friend to you than the foreign country of Germany, who wanted to exterminate all Jews.
Settling islands, wanting to take over Taiwan, trying to expand their global power, making friends with other world leaders who want to expand their power, etc.
In some situations that might be true but I think it depends. In some cases, the ruling class of your own country might be investing in a military which protects you, while a foreign government might want to invade your country and oppress you. For example, if you were an American Jew in WW2 then surely the US ruling class was a better friend to you than the foreign country of Germany, who wanted to exterminate all Jews.