Some 80,000 years ago modern humans began leaving Africa and settling the rest of the earth. We came to the end of that process only in the last century. The long term trend is for people to become ever more able to communicate and travel. The resulting homogenization is likely to culminate in the end of the nation-state as we know it.
The problem is that for the last 230 years or so, the nation-state, particularly the United States of America, has been the only earthly guarantor of individual liberty. By this I mean that we respect and enforce limits on what any group, including the nation-state, can do to any individual. (See the Bill of Rights for details.)
My solution is to be a partisan for individual civil liberty, to assert that it is a positive value for all people of all cultures and religions. My hope is that civil liberty will become so accepted and common as to be taken for granted all over the world. So that by the time the nation-state disappears, liberty will remain.
The problem is that, as the planetary society gets homogenized and crowded, as technology empowers individuals to do ever greater good or harm, as governments must therefore monitor individuals ever more closely, will we simply dumb down the concept of liberty to the point of being meaningless Newspeak?
In a free society the fundamental tension between the good of the collective and the good of the individual is never finally resolved. Going too far one way will crumble the society, and going too far the other will crush the individuals who make up the society.
And as we develop the biotechnological tools that will enable us to change what it means to be human, maintaining the balance between the individual and the collective will become ever more complicated, delicate, and difficult.
In a way, it's not my problem. I'm already middle-aged, and I have no progeny. But the rest of you will be sorry if you screw this up.