“How the hell do you negotiate with a party that reassures one day they won’t invade, and the next launches a major invasion?”
Context is important. Russia had troops mobilized on the border for weeks.
That is when you begin negotiations—before things get out of hand.
Imho Putin invaded because he concluded that the clowns in DC were more interested in name calling, finger pointing and virtue signaling than serious negotiations.
“Context” is that Xi asked Putin to wait until after the Olympics. The “negotiations” were a ruse.
Putin invaded because it is part of his oft stated desire / goal, and specifically because he thought: the West in general and the US in particular was politically weak, he could repeat past adventures, and that Ukraine would crumble in a few days.
Well, he was right about one.