On both sides of Atlantic, it's been shown the populist left can't yet win majorities. But it does have the young, and will have the future.
For the meantime, the centre and left need each other to win. Let's hope @Keir_Starmer remembers that.
We have seen the failure of the Ed Miliband years. He was (like Keir, I hope) someone who saw the potential of uniting left and centre to rebuild social democracy, but lacked confidence and mettle to make it happen.