They are in their own country. What’s the problem Z?
The Belarus govt. allowed Putin's forces to attack Ukraine from Belarusian territory. Thus, many thousands of Russian soldiers poured over the Belarusian border into Ukraine, invading it. According to the Rules of War, Belarus is thus a combatant. Ukraine would thus be completely entitled to counter-attack Belarus, launch missiles targeting Belarusian military installations, and to seize Belarusian territory.
Regards,
Bialorus is in the same position as Ukraine.
Bialorus or “White” Russia was one of the three parts of the former Rurikid “Kyivan Rus” confederation of duchies, the others being “Red” Russia/ruthenia which is now called Ukraina and “Black” Russia or Muscowy.
The colors are from the colors used by Eastern Slavs and Turkics and Mongols to denote cardinal directions (White for west, Black for north, Red for south, Gold for center and Blue for east — hence the “Golden horde” and the “Blue Gokturks”
Anyway, bialorus has a distinct language, culture and history from Muscowy. It has been badly wounded over the centuries, but still can recover.