Putin has, in fact, officially declared WAR and is conducting a full scale invasion "to demilitarize Ukraine". I guess Putin isn't afraid of Biden or CornPop.
I'll reiterate my personal view: America should stay the hell out of this. The Euros (particularly Germany) made themselves dependent on Russian and Ukrainian gas... now Russia will control both sources.
From the BBC:
Remember when he was campaigning in 2019?
"Send me to the White House, and Putin will know his days of tyranny and trying to intimidate the United States and those in Eastern Europe are over."
I'm not saying Trump could have done better because I just don't know. But he certainly could not do worse.