How to get power
New political structures at higher level than nations like the European Union (EU) are diluting the national power in favor of stability. Each nation tries to reach a balance between internal and external power, and so do it's neighbours. The bigger entities like the EU are big enough to absorb the power of a nation. Nevertheless they will try to strike the balance against each other, so the game goes on at a higher level.
Even if those nations uniting structures should one day cover the whole world (i.e. if the UN are going to become a real government body holding the monopoly of power), small groups will split internally and start again the neverending story of the struggle for power.