Irish policy makers are watching Scotland's referendum "with growing fascination and alarm", said Paul Gillespie in a paper published by The Institute for International and European Affairs, Ireland's answer to Chatham House.
The Yes campaign has already been billed as an "existential threat" to Northern Ireland. So too, argues Mr Gillespie, is David Cameron's commitment to an in-out referendum on Europe, which threatens to create a hard border across the north of the island. However, Ireland, still recovering from crisis, is far from ready to absorb the North.
Mr Gillespie, a former foreign editor of the Irish Times, said: "If the UK breaks up, then Irish unity would be put on the political agenda far more quickly than Irish political elites and voters north or south expect or desire.
"This is not to predict that outcome, but it is to say it would become a more urgent political option than now, with potentially rapidly changing preferences on all sides, including among unionists who would lose the object of their traditional loyalty.
"Its multiple stakeholders would have to redefine their interests radically."