There was no way Russia could allow America's proxy to take back the Crimea. If America's military thought it was possible, it would have tried. The Crimea is too important fto Russia's continuing status as a superpower.I believe the opportunity was squandered when Obama and the rest of the world allowed Russia to unilaterally annex Crimea in 2014. If there had been opposition then, I believe Putin would have been more cautious with his moves on Ukraine.
That at the time would have resulted in nuclear war, or if not, another capitulation by America as that which happened in Cuba/Turkey.
Putin is doing what is necessary because his superpower status says he can!
Glad to see you back taking part in the relevant issues my old friend!

