There isn't one simple answer here. This is partially about shoring up Russian reputation. Partially about Putin distracting people from a Russian economy that

There isn't one simple answer here. This is partially about shoring up Russian reputation. Partially about Putin distracting people from a Russian economy that has suffered under covid right after the state reformed the pension system. Partially about lashing back at what's perceived as Nato expansionism. Partially exploiting a time when Americans are most war weary due to the Afghanistan pullout. The rest of Nato is busy with wrecked balance sheets and other issues like global warming. Nobody is itching for a fight right now so it's a good time to press. And, lastly, probably good old fashion Russian incremental expansionism.