Finnish lawmakers narrowly approved controversial bill that will allow border guards to turn away third-country migrants attempting to enter from neighboring Russia

I don't normally interact with political tagged articles but I saw this one before I logged in.

What Finland is referencing here is not a theory, it's an established and modern war-tested tactic that Russia has already put into effect with great success.

Back when Russia overtook Crimea as part of their campaign to "free" the "more Russian than Ukrainian" population, they undertook numerous years-long campaigns to increase Russians presence and power within the territory. Some of the programs consisted of $30K payments for Russians to move to Crimea and the creation of mortgage programs and law changes that allowed the Russian elite to buy up large swaths of Crimean land to slowly force out ethnic native population.

Now thanks to the 2021 decree that makes it illegal for all non-russians to own land within the Russian territory of Crimea, they've sealed away any hope for Ukraine to take the place back. Either you become legally Russian and keep your house, or you have to leave.

I didn't vet this source but it seems to just be recounting the multi-prong tactics the Kremlin uses to overthrow from outside and within: https://jamestown.org/program/demographic-transformation-of-crimea-forced-migration-as-part-of-russias-hybrid-strategy/