Putin is, despite the claims from the administration and its media, a rational actor. Like every tyrant he sees no value in rhetoric except as assertions of strength or admissions of weakness.
Biden, like his former boss, keeps insulting and threatening Putin not from a position of strength, but as an admission of weakness. Biden calls for regime change and war crimes trials for Putin, and then slow walks shipments of weapons and refuses to transfer planes to Ukraine.
The message is the same as when Obama condemned Putin’s invasion of Crimea and then refused to provide meaningful armaments to Ukraine while slow walking shipments of boots.
Putin understands the message the same way a big dog understands when a little dog yaps.
Moscow isn’t paying attention to what Washington D.C. says, but what it does. And the real message from Biden is that he’s afraid of Putin, but looking to cover it up with tough talk.
Biden wants all the political benefits of siding with Ukraine, with none of the military risks.