Reckless and ruthless? Yes. But is Putin insane? No.

Declaring someone irrational leads to a place in which no one wants to negotiate, because, no one wants to talk to crazy people.
A number of things about Putin’s invasion of Ukraine are not in doubt: that it was a deeply criminal act; that it has been accompanied by great brutality on the ground; that it was based on extremely faulty intelligence; and that in consequence it involved extremely serious political and strategic miscalculations.