I'd say it would probably be America, Mexico, most of Europe, and Japan/Australia due to regional vulnerability.
V Russia/Iran/China (just for shits and giggles), some of the Easter bloc leftovers, and certain middle eastern allies.
Would not be easy due to our need to protect Japan/Australia from Chinese threats.
Meanwhile India and Pakistan along with the Koreas would just blow each other up along withSyria/Rebels and Israel is straight fucked.
South America would chill then take over the world with south Africa countries.