>Both China and Russia have claimed parts of other countries using the tactic of moving in their people to then use that as an excuse to annex or overtake those parts.

>Crimea for Russia as an example, but this is also true for other former Soviet states.

In Crimea, the proportion was 3 Russians for every Ukrainian for most of the time since at least 1897:

  1897:
  Russians 33%
  Ukrainians 11%

  1989
  Russians 67%
  Ukrainians 25%

Before 1954, Crimea was officially part of Russia, so it makes sense (Khrushev transferred it to Ukraine for infrastructure reasons).

Not sure what happened when the number of Ukrainians dropped from 24% to 15% between 2001 and 2014, I'm not aware of any mass migration during that period (independent Ukraine). On the contrary, the total population contracted from 2.4 mil to 2.2 mil (both Russians and Ukrainians).

I guess my advocacy is to identify it as a social pattern and then come up with some kind of global treaty against it similar to the geneva conventions. It'd take years, there'd be lots of negotiations, people way smarter than me would opine. I certainly don't have all the answers.

I can entertain the plausibility of this form of nationalism not being a catastrophe but I can't think of any times it worked out well.

On a personal note, I harbor particularly harsh judgement on my own nation, the USA, on this front. Unfortunately there's no way to unroll hundreds of years

How does this work when a group wants to move in to an area that's already completely in use by another group?