Outraged EU imposed sanctions on Belarus, who was forced then to turn to Russia for support.

Now Russia is calling the favor back and forcing him to send troops to Ukraine, which he doesn't want, both because it's a very unpopular move in Belarus, and also because it's pretty clear now that he'll incur heavy losses.

Lukashenko never wanted to be a Russia puppet, but it's funny how his decision to arrest a dissident at any cost basically lead to his country annexation by Russia, which he tried to prevent for 30 years.

Now there are a few more pieces to this story, like the previous elections in Belarus that he blatantly stole, and the fact that Russia was going to submit Belarus one way or the other anyway, but the fact remains that that one small decision greatly accelerated the process. Butterfly effect.