You mean the violent separatist insurgency from inside Ukraine, funded and equipped by Russia itself?
Any sovereign country has the right to put down wanton violence inside their own country
That’s not a valid reason to attack & invade
At least the good part is, Russia is getting their ass kicked on many fronts now
That’s not a valid reason to attack & invade
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A better reason is claiming that they have weapons of mass destruction, invading to find them, and then upon not finding them, setting up a puppet-government. They should have tried that in order to gain Western acceptance.