Built up a huge and active new membership of the party. Broke the seemingly unbreakable grip of the Mandelson/Campbell adherents over same. More or less single-handedly made soc-dem policies politically viable again. Prevented what would have amounted to a full fascist take-over of the country last year from seemingly nowhere.
We’re back in open season on Jez in the media now, and will be until the next election forces them to momentarily put the brickbats down, so things will seem bleak for a while (particularly with all of the rest of the awful shit currently going on). But even if he resigned tomorrow, we will have made huge strides forward in the last couple of years that can’t be taken away by a few twit-stalkers who have had their brains broken by Brexit yelling that he’s the worst thing that’s ever happened.
tl;dr dry your eyes, soldier.