In the studio complex where the hit drama <i>Game of Thrones</i> was filmed, it was appropriate that Mary Lou McDonald strode into the Belfast election count with the mistakable buzz of triumph among her team. Northern Ireland politics is regularly marked by dramatic moments that promise a historic turning point. The juncture opened by Ms McDonald, president of the all-Ireland Sinn Fein party, was that its victory would start a push for reunification of the island, cutting the tie to the UK. In the language of Northern Ireland politics, the process is referred to as a "border poll". Despite the anodyne name, the idea is both controversial and divisive – something that compounds the tensions created by the fragile make-up of the region. Sinn Fein’s election campaign for the 2022 Northern Ireland assembly said almost nothing about unification and, instead, stressed messages around working together to address cost of living and healthcare issues. Once the votes were in, the Dublin-based Ms McDonald threw off the restrain. Work for a border poll should start before the end of the decade, she declared. Indeed she would like it within five years. The change of tone was one aimed much more towards a wider audience beyond the British-run territory. If it pans out the way Ms McDonald would like it to, the outcome would be seismic. Sinn Fein in two decades has transformed from being the voice of the Irish Republican Army commanding less than 10 per cent of Northern Ireland votes and almost none in the Irish Republic. As of this week, it commands most seats in the Northern Ireland assembly. It has set its sights on the same goal in the Irish Parliament at the next general election in 2025. Because of the weak and transactional nature of the big Irish parties, it has good chance of doing so. That would give the tricolour-branded party an immense platform to further the reunification agenda. There be little doubt about what that would mean for Britain, Europe and indeed the overall shape of the West. The current tensions with Russia are bringing those into focus in ways not seen since the Cold War, or indeed the Second World War. When Russia’s state TV last week showed a mocked-up strike by a nuclear drone not only wiping out the UK, which it deems as principal enemy, there was outrage in Ireland. The country’s foreign ministry lodged a protest with Moscow. There were calls in the newspapers for Ireland to expel the Russian ambassador, something that hasn’t really been heard in London. A few days later, a Russia submarine was spotted off the north-west coast of Ireland, which is a non-aligned state. As such Northern Ireland is an important aspect of the UK's projection into the North Atlantic – and hence that of Nato. The strategic implications of Irish unity are considerable and not to be underplayed, even if they have been rarely discussed. There are several reasons why a rush to consider Irish unity can been discounted even after the poll result that has set everybody talking. In the first place the Sinn Fein campaign placed its northern leader, Michelle O’Neill, on its posters for its presidential-style campaign. Her words have been far more inclusive towards the Unionist tradition. Even Ms McDonald has also told voters from the other tradition “don’t be scared”. The overall percentage lead between Sinn Fein and its main rival, the Democratic Unionist Party, was 29 per cent to 23 per cent. But parties declaring themselves to be Unionists and parties that are Nationalist both garnered 40 per cent of the vote. A surge in the centrist Alliance Party has boosted the independents to 20 per cent. In effect the ratio of power in Northern Ireland is 4:4:2. There is almost zero chance that this calculus could be reordered by the establishment of a referendum on Irish unity. The toxic issue of Brexit has if anything entrenched the divisions between each side. Those in the middle may enjoy the advantages of Northern Ireland’s duality too much to make a jump for Irish unity. Global identity matters for all those involved in the process. Local identity matters even more. Polarisation has been turbo-charged by Brexit. Irish citizens in the south are also puzzled by the northern society and don’t easily understand how they could easily absorb hundreds of thousands of angry and “scared” northern Protestants. Still, the rise of Sinn Fein both north and south cannot be discounted. It is based on familiar social issues of inequality and frustration at the economic disparities throw up by the modern economy. The party’s ideological roots cannot be separated out by the fact that its electoral gains are based on different strands. The wisest in the party lay a different stress from Ms McDonald. They point to Brexit and say the last thing they want is a referendum that they win and then don’t have a clue what to do with their victory. Taking a step back, they see the Irish state as in need of overhaul. Northern Ireland would have to change, too, if it were to be absorbed into an all-island entity. Why not have a citizen's assembly to say a poll on Northern Ireland would be a vote on hitting the reset button across the whole of Ireland. That would be something worth voting for: the future.