i'm not a leader of any sort of country, but i fail to see how shelling and invading ukraine fixes that.

even if it were a quick and easy three day excursion to kyiv, congratulations! your newly annexed ukraine is now... right on the edge of nato poland. and other countries that were on the fence might be more likely to join, lest they be next in russia's sights.

granted, a lot of this analysis is from the standpoint that nato had no plans to be militarily aggressive with russia. if you assume nato was gearing up to use ukraine as a means to get invasion forces into russia, then that shifts things. but there's no evidence that was ever on the table.