We don't need tensions between The Republic of Ireland and Northern Ireland

The argument

This argument holds that the UK should have remained in the EU because leaving reopened one of the most dangerous fault lines in its recent history: the border between the Republic of Ireland and Northern Ireland, and the tensions that EU membership had helped lay to rest. The stakes here are uniquely grave. The Good Friday Agreement ended decades of violent conflict in Northern Ireland, and a crucial enabler of that peace was the effectively invisible border between North and South — possible because both the UK and Ireland were in the EU's single market and customs union, so goods and people moved freely with no infrastructure, checks or hard frontier. That open border let the two communities and economies intertwine and allowed national identity to feel less zero-sum. Brexit struck directly at this arrangement: leaving the single market and customs union meant a customs and regulatory boundary had to fall somewhere — either a hard border on the island of Ireland, anathema to the peace settlement, or a border in the Irish Sea between Northern Ireland and the rest of the UK, anathema to unionists. Either choice inflames a community, and the wrangling over it has indeed renewed political instability and sectarian tension. The argument's force is that some risks are not worth taking for any benefit. Reawakening the constitutional and sectarian frictions that cost so many lives, in exchange for the contested gains of leaving, is a reckless trade. Remaining in the EU kept the border problem dissolved and the peace's foundations undisturbed. From this standpoint, no Brexit dividend could justify destabilising the Irish peace. Because we do not need renewed tensions between the Republic of Ireland and Northern Ireland, this argument holds, the UK should have remained in the EU.

Premises

Counter-arguments

Critics of this argument accept the border difficulty and deny that it settles the question. The Good Friday Agreement contains no provision about customs arrangements: its mechanisms are consent, power-sharing, cross-border institutions and the principle that constitutional change requires a majority in Northern Ireland. The open border was a benefit of shared EU membership rather than a condition the settlement imposed, and treating it as the peace's foundation overstates what the agreement rests on. The dilemma was also managed rather than realised. No hard border was built on the island; the Protocol and then the Windsor Framework produced a differentiated arrangement with separated lanes for goods staying in Northern Ireland and goods moving on. Stormont did collapse over it, but the institutions have been suspended repeatedly since 1998 for unrelated reasons, including over welfare reform and a renewable heating scheme, so a suspension is a recurring feature of the settlement rather than evidence of a Brexit-specific mechanism. Structurally, the argument is also a single-issue veto: it holds that one risk outweighs every countervailing consideration, a form of reasoning that could decide any referendum by naming its gravest downside. Critics on the leave side argue that sovereignty, trade policy and immigration control were what the question was about and must be weighed rather than ruled out — and note that a principle forbidding any change to the arrangements would have told equally against deeper EU integration, to which unionist objections were also raised.

Rejecting the premises

[Rejecting P1] Critics reply that the Good Friday Agreement contains no provision on customs and rests on consent, power-sharing, cross-border institutions and majority consent for constitutional change, so the invisible border was a benefit of shared membership rather than a condition of the peace. [Rejecting P2] The dilemma was managed rather than realised: no hard border was built, the Protocol and Windsor Framework created a differentiated arrangement, and Stormont has been suspended repeatedly since 1998 over unrelated matters. [Rejecting P3] The argument functions as a single-issue veto, holding that one risk outweighs all countervailing considerations — reasoning that could decide any referendum by naming its gravest downside.