A nation state has power and it isdivided into two parts, the first one is the elite. Elite people are the ones who have education and are mostly wealthy; usually they are the ones whocontrol the political power. The other part is the mass, which is the rest of the population, the ones who are not educated and lower classes.
All stateshave power, ones have more power than others, and thus systems are created. Classic systems are the Metternichian and the Bismarckian, both of themwere a balance of power, or at least tried to be. The new types of systems are: multipolar, unipolar, counterweight, balance-of-power, globalization,clash of civilization and resources.
Strong states have to have sovereignty, have to be able to rule and govern its own territory. A country that hassovereignty also have to have military force, a good economy and most of the times being a democracy In International Relations we can see threedifferent ideologies:
The first one is capitalism and countries like the US, Brazil and European Union are ruled by it.
The second one is socialism andcountries like Norway and Denmark are ruled under it
And the last one is communism in which countires like China, Cuba and North Korea are ruled by.