ST. JOHN’S, N.L.—The position of chief of staff to a prime minister or premier is among the most powerful roles in government. Chiefs of staff have a unique perch at the top of the government hierarchy. They are the main intermediary with ministers and their staff. They perform a largely clandestine role, unknown to most Canadians, even to most public servants. So when a former chief of staff has something to say we should listen.