The untimely death of Martin McGuinness earlier this year, and the confirmation last week that Gerry Adams will signal plans for his own departure in November, mean that Sinn Féin is now undergoing the most radical change in its modern history.

But some things remain the same. For the best part of the last decade, Pearse Doherty has been producing pre-budget submissions that have been derided by the political establishment. “Shinnernomics,” some have...