Proponents of Irish Unity have had a good run. The Good Friday Agreement opened the door to a Border Poll and then Brexit propelled them towards the promised land. But context is all. And as with much else, the Trump Revolution has changed everything. For centuries, London felt threatened from the west. Until finally, the end of the Cold War heralded a seismic shift. Just five months after the fall of the Berlin Wall, the words in April 1990 of the then Secretary of State for Northern Ireland Peter Brooke, summarised the historic change: ‘The UK has no selfish strategic…