Which reminds me. Half of the question is how the supers come about.

Do supers come about from technology? Then high tech nations like Europe, Britain, America, China, etc... all get an advantge. Whether its cybernetics, super-serums, or just plain ass vita rays.

Do supers come from random mutation in the population? Then most countries are in trouble, since most western nations with all the guns and the weaponry are in the distinct minority on earth. That means lots and lots of people, who are not necessarily friendly to America or Europe, get superpowers, making things get ugly.