This idea was originally meant for my educational online store, Level 3, Topics Biology & Climate.
A country decides to “absolutely ruin” all the nature and areas at their border.
Why? To make it completely impossible for anyone to invade (and/or migrate to it?)
They set stuff on fire, release toxic gasses, let the biggest predators run wild, etcetera.
They do it in such a way that they are not harmed by it—they have merely permanently lost some land. It just becomes this impossible wasteland of death for anyone else to trek through.
Maybe, though, it’s revealed that there is a way to get in and out of the country (because president needs it, people want it, migration was still desired) … and that turns out to be a weak point that another country tries to exploit?