He is effectively appealing to those, perhaps, some 30% of Catholics that may emotionally feel themselves to be Nationalist, but who are likely to put economic questions foremost when considering the consequences of constitutional change.

As most Germans will say, there were cultural differences that grew in the lifespan of the DDR but in the main that did not the reflect the historical and cultural split in Germany. As one German teacher remarked to me back in the 80s, "when they cut the country, they cut it the wrong way - it should have been North South, not East West".

The analogy with the Berlin Wall is an interesting one. It seemed to require the moral collapse of eastern government to propel the population towards a western lifestyle that they'd seen on tv, but had been forceably (on pain of death) kept from. It's hard to see what might act similarly on the (for want of a better term) 'dissenting Catholics' in Northern Ireland.