Analysis: the relationship between the UK and EU will continue to impact electoral trends in Northern Ireland

Election results in Northen Ireland are often interpreted as a referendum on its constitutional status and the likelihood of a united Ireland. The debate around this has accelerated since the loss of the unionist majority in the 2016 Northern Ireland Assembly election, which was followed a month later by the Brexit referendum, in which a majority of voters in the North voted to remain in the European Union.

It is clear that voting trends have changed in Northern Ireland over the last decade with both the loss of the unionist majority and the electoral growth of parties in the centre ground, with the Alliance Party being the most prominent of these. Opinion polls suggest that this pattern, summarised in the following graph for elections to the Assembly and Westminster since 2015, is set to continue with Alliance projected to potentially become the third largest party in the Assembly.

While demographic change and many issues influence voting patterns, it is notable that these changes began in the run up to the Brexit referendum and have continued since. We have seen parties that are not primarily focused on the constitutional status of Northern Ireland enjoying particularly rapid growth.

The relationship between the UK and EU which has influenced voting choices across Britain also seems to be having an impact on electoral trends in Northern Ireland. The Alliance Party won one of three seats in the final European Parliament election in Northern Ireland in 2019. Sinn Féin became the lead party in opinion polls in 2020 after Britain officially left the EU with the deal that established the Northern Ireland Protocol.

Media attention in the lead up to the election has focused on the likelihood of Sinn Féin overtaking the DUP as the largest party and the impact a nationalist First Minister would have on prospects for Irish unity. Protests from some Loyalists and the leaders of the TUV and DUP against the Northern Ireland Protocol have also been widely discussed.

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From RTÉ Radio 1's Today with Claire Byrne, Prof Deirdre Heenan from Ulster University and Mark Simpson from BBC News Northern Ireland on next month's Northern Ireland election

Despite the strength of anti-protocol sentiment in these protests, the predicted outcome of the election is that the majority of elected members will still be in favour of EU membership and the Protocol. The UUP favoured remaining in the EU but is opposed to the protocol.

The level of support for parties that support the protocol, which they view as the best option currently available to manage the impact leaving the EU has on Northern Ireland, has been consistent in elections since the referendum as this graph shows. The level of support for pro and anti-protocol parties mirrors the referendum result in which 55.8% of Northern Irish voters wanted to remain in the EU while 44.2% voted to leave.

The issues that influence how Northern Irish citizens vote - and how many turn out - on May the 5th will be complex. These include economic and moral issues alongside the protocol, Northern Ireland's constitutional status and who they would prefer as First Minister.

But there are clear links that can be made between views on the relationship with the EU and Northern Ireland's constitutional future. This can be seen on the map below which shows that constituencies with a majority of voters in favour of leaving the EU were those with a majority Unionist population (with the exception of remain voting East Derry and Strangford.)

Voting patterns in and since the Brexit referendum indicate that views on EU membership are linked to views on Northern Ireland's constitutional future, with parties who support maintaining the union with Britain explicitly opposed to the Northern Ireland Protocol. Opposition to Brexit also appears to be a factor driving support for Sinn Féin and the Alliance Party in particular, with opinion polls suggesting that they are likely to become the largest and third largest parties respectively in the Assembly in May.

But however these two parties fare at the election, the wider trends look guaranteed to continue on the day. The most pessimistic predictions of support for these parties would result in better results for other pro-protocol parties. Increased support for the DUP would lead to them retaining their current position as the largest party, a situation which would most likely come at the expense of other anti-protocol Unionist parties.

It is likely that the next Assembly will again have a pro-protocol majority, with neither unionists or nationalists able to gain a majority as parties on the constitutional centre ground continue to grow. These ongoing trends will ensure that Northern Ireland continues to hold a central role in discussions about the future of relations across these Islands and with the EU.

The views expressed here are those of the author and do not represent or reflect the views of RTÉ