But the question still remains of what is done about it now. What are you suggesting is to be done right now to help Ukraine win and stop his march? What are the choices here?
This depends on Putin's actions. If things are going as they are, he will eventually run out of resources because of poor execution, logistics, and morale - all at a time when his domestic economy is going to collapse.
He will try to negotiate his way out of this by attempting to gain a concession from the Ukrainians; which could be anything ranging from the annexation of Donbas, Ukrainian recognition of Crimea as Russian territory, and some sort of written assurance that Ukraine doesn't join NATO.The Ukrainians, who are generally repelling and frustrating Russian advances - and with the knowledge that Putin's resources are not limitless - will not be incentivized to capitulate under terms Putin already demanded before the invasion. Putin will then have to make a choice as to whether he wants to double down on violence, use a thermobaric weapon, a WMD etc. in a desprate attempt to get the Ukrainans to surrender so he can force a negotiated settlement that is favorable to him, then call for a ceasefire under the pretext that he got something out of his "special operation".
NATO and Biden in particular, have to have a plan in place in case he uses a tactical nuke or chemical/biological weapon inside Ukraine. They can't use the same cowardly logic of "it would start WW3 if we intervened", because all it would do is incentivize Putin to continue doing what he's doing because he knows everyone is too scared to intervene. There has to be some sort of line of demarcation that is drawn (which should be the use of WMDs in Ukraine) that lets him know his actions will result in an immediate escalation.
NATO should also look at setting up a No Fly Zone in areas of Ukraine where there is no fighting and deconflict it with the Russians to prevent any accidents. This was done successfully in Syria and should be on the table in Ukraine as well.
