Balance of power. That was what founded the nation when the mountains and the plains regions joined together. That was what put a stop to the wars that had been going on and unified the country.
It was the fact that both sides had the power to both harm or help one another that led to Lodenore being formed. Obviously the power between North and South Lodenore isn’t military any more, but it’s something that is always being discussed and reworked in the political arena.