How would the time-stream of humanity sort itself into coalitions?

Kevin Riste, a loyal MR reader, and perhaps a loyal Philip Jose Farmer reader, asks me:

…if all of the people in recent history (since, say, 10,000 BC or so?) through today were somehow gathered at a sort of “conference,” do you have any predictions for how they would align themselves over time? what distinctions would be most significant? assuming language barriers are overcome to an extent, since that seems most significant.. male/female? by decades? nerds/jocks?

Let’s assume that different eras send roughly equal numbers of people to the conference and let’s make the conference small enough to be manageable.  No one can bring weapons or iPhones.  I believe the most significant coalition would be “rulers vs. ruled.”  On one side of the banquet table would sit modern Americans, members of the Roman Senate and Imperium, Ghenghis Khan supporters, eighteenth century Brits, 15th century Nahuas, Song Dynasty fans, and so on.  They would commiserate over the plight of having to make all those tough militaristic decisions and how little they are appreciated for it.  They would have plenty of disagreements, but ultimately they could be unified if ever the other side threatened to take over.  The Albanians, Armenians, Angolans, Bolivians, the less powerful Native American groups, and others would show up on the other side and trade stories of commiseration.  They too would have plenty of disagreements, but with less underlying unity.

In fact there is a such a conference, in atemporal form, and it is called the United Nations.