Behind this facade disappears the distinction between the just, national life-interests of a people, and the aggressive tendencies of imperialist chauvinism. Source
According to the source, this section is about the "fetishization of the nation".
"the just, national life-interests of a people" would then mean the natural needs and wishes of a nation or people as a society. This could be things like security, employment, cultural freedom etc.
This is contrasted with "the aggressive tendencies of imperialist chauvinism" which could be expansionism, projected power, cultural domination etc.