As Tony Blair’s chief of staff, Jonathan Powell was the ultimate backroom operator – now he is back at the heart of Labour’s foreign policy… and prime target for the opposition and right-wing press, says John Rentoul W hen Keir Starmer cancelled Rishi Sunak’s choice of national security adviser and appointed Jonathan Powell instead, it seemed to be a triumph for “serious” government. Tony Blair’s premiership was a long time ago, but it looks increasingly like a model of good administration, and