Ed Miliband is the least of Labour’s problems. Its troubles go far deeper than any individual. They are structural and, potentially, fatal. It is certainly easier for Labour MPs, and ultimately more comforting, to concentrate on Miliband’s deficiencies as a leader than the existential crisis facing the left. But until somebody comes up with an answer to the question of what the party is for — in an era of austerity and globalisation — it will be stuck in a death spiral.