The UK is a founding and leading member of the North Atlantic Treaty Organisation (Nato). That makes Northern Ireland, its territory and residents, part of that alliance.
Nato consists of the US, Canada and 30 European states – 23 of which are member-states of the European Union. Nato members are pledged “one for all”: an attack on any one member state is to be treated as an attack on all. Ireland is one of four EU member states outside Nato.
Ireland is not neutral by virtue of its Constitution or an international treaty. It is militarily neutral because that has been government policy since full sovereignty was established in 1937.
Unification, however, would mean that Ireland’s original reason for not joining Nato – partition – would be obsolete.
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So, in the event of reunification would membership of Nato be considered? Or would a united Ireland maintain the Republic’s policy of military neutrality and take Northern Ireland not only out of the UK but also out of Nato?
To understand the views of the public, North and South, on these issues, we asked respondents in the ARINS/Irish Times surveys that if unification were to happen whether a united Ireland should join Nato.
Southerners are firmly opposed. Half (49 per cent) are against membership. Just one – fifth are in favour (19 per cent). In contrast, the public in the North is moderately supportive of Nato membership under unification. More than two – fifths (43 per cent) are in favour, while one quarter (25 per cent) are opposed.
The overall northern percentages mask significant internal differences, however.
Protestants are firmly supportive of Nato membership under unification, by a proportion of nearly four to one (55 to 14 per cent). Catholics are evenly balanced: 31 per cent are in favour and 35 per cent against. The “Others” are also evenly balanced, but tilt positive: 34 per cent in favour, with 30 per cent opposed.
[ Support for Irish unification growing in Northern Ireland, poll finds ]
Only one in six (17 per cent) of southern Sinn Féin supporters favour joining Nato under unification. In contrast, northern Sinn Féin supporters are almost twice as supportive (31 per cent). They indicate more pro-Nato sentiment than either Fianna Fáil or Fine Gael supporters.
Three-fifths of supporters of the two main unionist parties favour Nato membership under unification, as do, intriguingly, the same proportion of Alliance supporters.
The Commonwealth
Unification would also result in Northern Ireland leaving the Commonwealth and fully rejoining the EU. We asked respondents whether, in the context of unionists having to join the EU under unity, a united Ireland should balance this shift by rejoining the Commonwealth.
Southerners are strongly opposed. Two-thirds are against (67 per cent). Just over one in ten are in favour (11 per cent).
The negative balance of opinion on the Commonwealth (-56) is almost double the comparable negative balance on Nato membership (-30). Southern antipathy to both organisations is strong, but Nato is much more palatable than the Commonwealth.
Northern Catholics are also opposed to the Commonwealth (with a negative balance of -32), which contrasts with their near even split on Nato.
Northern Protestants are somewhat more in favour of Nato under unification (+41 balance) than the Commonwealth (+34). There is also more support among the “Others” for joining Nato (34 per cent) than the Commonwealth (22 per cent).
Differences between supporters of political parties on Commonwealth membership are greater than they are on Nato. Fewer than one in 10 Southern Sinn Féin supporters favour Commonwealth membership, compared with almost two-thirds (65 per cent) of the supporters of the main unionist party, the DUP: a difference of 56 percentage points, greater than the equivalent difference on Nato (42 percentage points).
Nato is therefore less strongly linked to unionist-nationalist party differences than the Commonwealth.
Southern and northern Catholic opinion may be less hostile to Nato, a US-led military alliance, because they see the Commonwealth as a British institution and, perhaps, they separate their thinking on security in the North Atlantic from their cultural preferences.
These findings suggest something important: Southerners and northern Catholics, and southern parties and northern nationalist parties, in search of workable compromises on international alignments to facilitate Irish unification, would find it easier to accept Nato membership than that of the Commonwealth.
Supporters of neutrality, who emphasise the peacemaking contribution that a postcolonial and non-aligned Ireland makes in global affairs, will be dismayed by discussion of Ireland joining Nato.
For others, by contrast, the plausibility of moving from neutrality to Nato membership is highlighted by the recent decisions of Finland and Sweden to join Nato after Russia’s 2022 invasion of Ukraine.
Ireland is now the sole western EU member state that is neutral by policy choice, ie without being obliged to be neutral by its constitution or by treaty. Cyprus is not free to make that choice because Turkey will veto its membership without a comprehensive settlement of the island.
Irish Nato membership under unification would reduce the changes faced by northern Protestants opposed to unity. It would directly align Ireland with Britain and commit the two states to their joint defence and would align Ireland’s security policy with one of its principal economic policies: attracting and keeping US foreign direct investment within the European single market.
Younger Dublin women opposed to Nato
But anyone contemplating joining Nato, and ending Ireland’s long-standing policy of military neutrality, should know that certain demographic groups in the Republic will be hard to persuade.
Among the public in the Republic, 19 per cent favour Nato membership under unification and 49 per cent are opposed, a negative balance of -30.
Opposition, however, is stronger among women (a negative balance of -36) than men (-24); stronger among people under the age of 50 (-35) than 50 or older (-22); and among people in Dublin (-45) than outside Dublin (-24).
These demographic effects interact. Among older men who live outside Dublin, opinion on Nato is equally balanced: 35 per cent are in favour and 36 per cent against.
In stark contrast, among younger Dublin women only one in 20 (5 per cent) are in favour of Nato membership under unification while seven in 10 (71 per cent) are opposed.
In the North, there is not much difference between men and women in their views on joining Nato under unification, either among the public overall, or when we disaggregate by religious community of origin.
Similar to the Republic, however, we find that age and place matter.
The overall balance of opinion in the North is favourable to Nato membership (+18), but enthusiasm is less in Belfast (+10) than outside it (+20). This effect is particularly noteworthy among Catholics. Outside Belfast, Catholics are evenly divided with 32 per cent in favour and 32 per cent opposed, but in Belfast almost half (46 per cent) are against and only just over one quarter in favour (28 per cent).
There are also strong age effects. In the North overall enthusiasm for Nato is greater among older people (+26) than those under 50 (+11). This effect is particularly strong among Protestants. Younger Protestants are three times as likely to want to join Nato as not join (47 per cent to 15 per cent) while older Protestants are five times more likely to favour membership than oppose it (63 per cent to 13 per cent).
In short, on our island our views range from highly Nato-sceptical younger women in Dublin to strongly Nato-enthusiastic older Protestants in the North.
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