“this melancholy decision” is, I suppose, one way to word the abandonment of Moscow. The emperor is not really a man of any great action, is he. I suppose Tolstoy is showing us that the further up the privileged food-chain we climb, the more useless everyone becomes. While Pierre runs around saving children and beating up brigands, the rich ebb and flow to the whim of an impotent figurehead. Typical.