He’s definitely a socialist but I’m not sure exactly how far. I think his choices were as you say ‘political suicide’ or basically becoming Bernie which isn’t ideal. He made the best decision from what he had, it’s better to be a dissenting voice in parliament than an ineffectual Prime Minister. Ultimately the political establishment would never allow real change as we all know and I only hope Corbyn trying that path and failing radicalised some would-be socdems.