He means that he's looking for a politician who is a partisan of the left but who does not play partisan politics. So, as you say, someone like Bernie Sanders

He means that he's looking for a politician who is a partisan of the left but who does not play partisan politics. So, as you say, someone like Bernie Sanders who is a social democrat (and therefore who by definition is someone a large swathe of the population loathes instinctively) but who is able to communicate to both the left and the right saying, “Yes, I understand your fears but look, it’s not right and we can do better than this” I think it's a very tough ask. Inequality is breeding division and extremism, I don't see how one magic or special person can appeal to both sides of the aisle. In a way, nearly all politicians are like Macron fiddling while Paris burns.