What about time of flight? The physically closest witness to you wins.
I got this idea when Apple impressed me with their unlocking tech, if you have an Apple watch you can unlock your computer more easily. The do this by measuring the time the signals take to arrive. From what I see of the EU and other global governance, that what is far away might as well be disconnected. You'd want your merchant and bank to be local. Mutual benefits create friendships.
I think it is crucial to have a fair distribution of power but also we can see that it is not easy to find the right incentives which do that.