For the independence and freedom of their country and against occupation. These would seem like the obvious answers. But during any war, you’ll have ideological commentators trying to claim that the ‘goodguys’ are fighting for their ideals. The chief of MI6 claimed that maybe the most important values the Ukrainians were fighting for were LGBT rights. Yet now we’re being told the Ukrainians are fighting for democracy and the rule of law.  This is why the European Commission cannot reach a deal with Poland to finally give it access to the Covid recovery fund that nearly all the other member states have been given access to, because Poland is totally undermining the rule of law, while countries like Spain, the Netherlands and Sweden perfectly respect it. Really.
Warsaw Pact comparisons
Lukashenko redux or Ukraine prequel ?