Interesting question! I think the opposite, actually, that unless we unite we’ll destroy the world. United we stand, divided we fall, and so on.
Thing is that we all have a view of freedom, rights, law and order, healthcare, and they don’t really mesh around the world. For me, the UN declaration of rights, the UN declaration of childrens’s rights, the UN agreement of racist organisations not having the right to political power, are things I stand behind. Many countries do not. As long as international law is decided by might or economic power it will not work – because the standards are not the same for small or poor countries vs big and powerful countries.
There are more reasons, but the biggest one is that we’re killing ourselves by destroying our environment and unless we can cultivate nature in a sustainable way and make sure that everyone have similar possiblities, chances, and resourses (at least a lowest level that is acceptable) we will, sooner or later, cause a catastrophy that we might not be able to reverse.