If Putin really wanted to, he could conquer Ukraine within a week.
There's a reason why he's fighting a conventional ground war without the use of airstrikes or targeting civilians. In fact, he's doing everything he can to minimize civilian casualties.
So keeping his army in Russia would have caused more civilian casualties?
You are shilling for Putin for some reason.
Shelling cities, bombing civilian targets, threatening cities with destruction unless they surrender and attacking urban areas of neighboring countries are all actions that are done based on the premise of killing and wounding civilians.
Look at the little girl in the linked photo and tell me you think doing that is a good idea. I'd post the image directly but it is probably too graphic for many FR readers.
Have a look and tell us what you think.