Turning points in politics are typically created by two key factors. The first is crises; the second is changes in leadership. Labour’s fortunes decisively changed in the ‘90s with the Black Wednesday crisis, only months after losing an election all assumed we could not lose. David Cameron undoubtedly seized on Tony Blair’s departure and cemented his challenger status against a Prime Minister far less nimble at the Despatch Box. Right now in Scottish politics we have both factors at play. The Brexit crisis has...