Peter Robinson may have retired as DUP leader eight years ago but the pragmatism that defined his activities as the party’s most effective strategist resurfaced this week, when Jeffrey Donaldson decided to end the DUP’s period of self-imposed exile and return to power-sharing. Robinson was the one who, in early December, suggested that the DUP needed to learn from republicans and bank as much as they could from negotiations, rather than pursue an all-or-nothing policy. He talked up the merits of revisiting unfinished business once back from the wilderness inside the tent, participating in devolved government. Eventually, Jeffrey Donaldson decided…