The peoples themselves do not derive any gain from victory. The individual citizens are not enriched if their rulers expand the size of their realm by annexing a province. For the people wars do not pay. The only cause of armed conflict is the greed of autocrats. The substitution of representative government for royal despotism will abolish war altogether.
Democracies are peaceful.
It is no concern of theirs whether their nation's sovereignty stretches over a larger or smaller territory. They will treat territorial problems without bias and passion. They will settle them peacefully. What is needed to make peace durable is to dethrone the despots. This, of course, cannot be achieved peacefully.