Indigenous sovereignty you say? I agree! England for the English, France for the French, Germany for the Germans, and all that, right? Clearly something has to be done about all these colonizers pouring in and undermining indigenous sovereignty by forming voting blocks and electing their own to force their non-indigenous culture on these regions. Case in point: Sadiq Khan. I suggest two possibilities. Either change the citizenship rules of people coming in so they can't vote (as many ex-pats in non-white parts of the world can't), or have some kind of immigration restrictions to keep them from coming over in such large numbers in the first place...
Seriously, if a bunch of white people moved en masse to some country in the middle east for some reason and elected a WASP mayor of its capitol city, how do you think these people would take it? Most of them don't recognize Afrikaaners who have lived in South Africa for 400 years as having any legitimate right to reside there.