The wisdom of Karl, a resourceful plumber from Ringsend, might have currency in Northern Ireland politics during the first weeks of this new year. Our paths crossed recently when Karl was replacing a tap in the bathroom sink of a house in Harold’s Cross. Many years of dispensing hot water had eroded the tap’s threads. Karl’s well-travelled wrenches had failed to loosen the fitting. So, in an effort to soften the obstinate metal, he introduced heat from a blow lamp. “One of the things I’ve learned about plumbing over the years” he explained, “is you have got to be prepared…