One thing that would quickly start to happen is a lot of the smaller countries would either be forcefully taken over or be quieted down. Most countries have neighbours they do not share good relations with - and with nuclear armament - bigger of 2 could easily pose nuclear threat and have a much bigger say in their arguments. This could mean taking over contested/disputed lands or some kind of minearl deals being forcefully signed. Soon the total world country count would start to decrease purely because of this (annd would actually accelerate until a point where most countries would form coallitions with some nuclear power and sum total of power on both (or all sides in general) be roughly comparable such that no one poses a greater threat to another and not have an equal threat back at them.
One thing that would quickly start to happen is a lot of the smaller countries would either be forcefully taken over or be quieted down. Most countries have neighbours they do not share good relations with - and with nuclear armament - bigger of 2 could easily pose nuclear threat and have a much bigger say in their arguments. This could mean taking over contested/disputed lands or some kind of minearl deals being forcefully signed. Soon the total world country count would start to decrease purely because of this (annd would actually accelerate until a point where most countries would form coallitions with some nuclear power and sum total of power on both (or all sides in general) be roughly comparable such that no one poses a greater threat to another and not have an equal threat back at them.