Brexit and the Good Friday Agreement - An Explainer

03 Dec 2020 – Written by Alani Sweezy & Alex Yeandle


  • The Good Friday Agreement, in place since 1998, has helped bring peace to the island of Ireland, an area previously marred with violent conflict.

  • The Agreement rests on an open economic border between Northern Ireland and the Republic of Ireland, something that was underwritten by both the UK and the Republic being members of the EU Single Market.

  • As the UK pursues a ‘hard’ Brexit, which includes leaving the Single Market with the threat of breaking international law, there is a risk that the reintroduction of economic barriers in Ireland will undermine the Good Friday Agreement and could fuel conflict.

  • The EU has strong incentives to avoid this, both to signal that it is willing to protect a smaller member state, and that it is serious about the rule of law in the face of continued disputes with Hungary and Poland.

  • The US, and in particular the incoming Biden-Harris administration, also have strong incentives to support Ireland and the EU as they begin to reverse Trump’s withdrawal from the international community.


Britain’s exit from the European Union has generated a constitutional crisis for the British State. The stability of Northern Ireland, one of the four nations that make up the United Kingdom, has been supported by the Good Friday Agreement. Yet this agreement, and many of its practical measures, are predicated on Britain’s continued EU membership. Britain’s departure has generated a host of constitutional questions, which if not properly addressed could risk a breakdown of peace in the region.

This article seeks to answer why the Good Friday Agreement matters, and why it matters so much not just to the UK and the Republic of Ireland, but to the EU and, increasingly, the United States. First, the context and scope of the agreement are outlined, showing the issues that Britain’s departure from the European Union raises. The particular incentives of the European Union and the United States are then explored in further detail. The article argues that peace on the island of Ireland is a strategic goal in itself, but defending it allows the EU and the US to signal a broader commitment to a law-based international order too.

What is the Good Friday Agreement?

The Good Friday Agreement (GFA) was the culmination of a political peace process between Ireland and Northern Ireland. A brief discussion of “the Troubles” – a prolonged period of violence in Northern Ireland – highlights both the importance and success of the GFA. We then consider the painstaking nature of how compromise was reached, underpinning its fragility.

For much of its history, the island of Ireland was part of the United Kingdom (UK). This generated deep political divides between Unionists (who wished to remain part of the union of the UK) and Nationalists (who wished to join the Republic of Ireland, an independent sovereign state). Unionists tended to be Protestant, Nationalists tended to be Catholic, but religion itself was not the important divide, it just happened to correlate with political differences.

When Ireland was granted quasi-independence in the 1920s (through the creation of the Irish Free State), the six counties that comprise Northern Ireland were partitioned out and remained part of the UK. Part of the reason for this is that, in constituencies in what is now Northern Ireland, Unionist parties performed exceptionally well in the 1918 UK general election. Elsewhere, Nationalist parties were far more successful.

This institutional arrangement did not neutralise the political divide, however. Within Northern Ireland there was, by definition, a majority Unionist (Protestant) population. This spilt over into material disadvantage for Nationalists (Catholics) in the region, which fuelled animosity and ultimately formed the basis for radicalisation. Due to the majoritarian electoral system, Nationalists were also systematically excluded from formal political power. Both groups engaged in violence against the other and much of Northern Ireland became segregated into Unionist and Nationalist communities that did not interact. Nationalist groups engaged in terror attacks in England throughout the 1980s and 1990s, including attempts to assassinate the British Prime Minister. British security forces became increasingly more aggressive in managing conflict, with key civil liberties oftentimes being neglected.

The Good Friday Agreement was the outcome of years of negotiation between the United Kingdom and Republic of Ireland Governments, alongside representatives from various Unionist and Nationalist organisations. The agreement sought to remove the political and economic importance of the Northern Irish border, guaranteeing that the border remain open at all times and that Northern Irish citizens were automatically entitled to Irish passports if they requested them. Given that the UK and the Republic were both members of the EU single market, a porous political and economic border could be easily introduced in practical terms. The agreement also negotiated various ceasefires and the decommissioning of weapons, and importantly introduced a new political executive that institutionalised power sharing, such that nationalists could no longer be systematically excluded from power.

The United States assisted in brokering the agreement, and it received praise from around the globe. British and Irish politicians from all sides of the political spectrum recognise the depth of achievement, and the difficulty in agreeing a peaceful compromise, given the preceding violence and polarisation. The GFA is unique but fragile – there are fears that if parts of the agreement are reneged upon, violence may resume. It is through this fragility that the Brexit process represents a risk. It is to this issue that we now turn.

Brexit and the Good Friday Agreement – What’s the problem?

After a drastic chain of events that resulted in the Brexit referendum, voters in the United Kingdom cast their votes on 23 June 2016 to leave the European Union (Wincott et al., 2017). Not only did these results shock political elites and voters in the UK but also spectators around the world. Henley (2016) notes that referenda often reduce complex questions to binary choices of yes or no. In a world where many societies are heavily polarized on many issues, such questions allow actors to play on fears that are already present, distort reality and appeal to emotion. Due to this, voters often see referenda as a way to voice their discontent, yet politicians may fail to discuss the complexities and consequences of issues.  Indeed, in the Brexit referendum, the Leave campaign consistently implied that the UK would stay in the EU single market, neutralising the need for changes at the Northern Irish border.

At the end of January 2020, a withdrawal agreement was reached between the UK and EU. The UK remains subject to single market law until 1st January 2021, but arrangements after this are still uncertain (Edgington, 2019). The withdrawal agreement makes specific mention to ensuring that the Good Friday Agreement remains intact after the transition period ends. This entails maintaining a soft border and free movement between the Republic of Ireland and Northern Ireland.

The UK has signalled its desire to leave the single market, introducing trade and immigration barriers with the EU for the first time in decades. This is problematic, since the introduction of a trade border undermines the provisions of the GFA. The British Government insists that a ‘hard’ border (complete with customs points and infrastructures) will not be required, but this is difficult to square with its insistence that goods from the EU will no longer be allowed to enter the UK freely. The withdrawal agreement contains provisions for customs checks between Northern Ireland and the rest of the UK, at least as a form of backstop. But such an arrangement would introduce an effective economic border within the UK. This would be a constitutionally troubling position from which the British Government has implied it may renege, even though doing so would breach international law. But its potential sanction for doing this is conditioned by the broader international community, of which the EU and United States form a key part. We hence now turn to examine why the EU and the US have such strong incentives to ensure the GFA is upheld.

Why does the EU care about the GFA?

The EU has two key reasons to be concerned about the impact of Brexit on the GFA, each revolving around the signal that their response sends to other actors.

Firstly, the GFA and Brexit deal allow the EU to send a Protective Signal to its members. Intrinsically, there is the fundamental point that the Republic of Ireland is an EU member state, so the EU is treaty-bound to prioritise its interests in negotiations. It is also not in the EU’s interest for there to be prolonged economic and social unrest involving its territory; this would be an anathema to its selling point as an organisation that promotes peace and the four freedoms (European Commission, 2020a). Extrinsically, solidarity to a small member state provides a signal to others of the strength that comes from being part of the union. This might work to reassure peripheral members bordering Russia that the EU would provide support in the event of encroachment. It might also undermine the success and drive of eurosceptic elites domestically, by allowing pro-Europeans to convincingly answer the question “What does Europe ever do for us?”.

Secondly, the negotiations allow the EU to send a Warning Signal in the face of democratic backsliding and declining respect for an international law-based order. The EU interacts with and seeks to influence a host of countries, with one of its key foreign policy interests being the promotion of a liberal, democratic, law based partnership of sovereign states. A large part of the GFA dispute revolves around the UK reneging from its legal obligations, and if the EU is seen to come down hard on this then it signals to potential trade partners, not to mention Hungary or Poland, that the EU will not be pushed. This, of course, would entail risks. Brinkmanship in the Brexit negotiations might ultimately end in a ‘no deal’ outcome, a worse endgame for both parties for an array of social, political and economic rationales.  For this reason it is important that the EU has powerful allies from whom it can seek support. With this in mind, we now turn to consider the role of the United States.

Why does the US care and how have they become involved?

Recently, members of Congress, as well as President-elect Joe Biden, have voiced their concerns regarding Brexit and the integrity of the Good Friday Agreement. But some may wonder why America is involved and what exactly is at stake.

As previously mentioned, America played a major role in the development and signing of the Good Friday Agreement, so much so that it is a guarantor of the Treaty. While having minimal involvement in Northern Ireland in the early half of the century, intense lobbying by key Irish-American figures, alongside the election of Bill Clinton (himself an Irish-American) prompted the US to play a more active role. US actors had deep concerns about discrimination and sectarian intimidation of the Catholic minority in Northern Ireland, but promoting peace overseas echoed its foreign policy objectives more generally

Recognising that Irish peace, stability and prosperity were intrinsically linked, Clinton hence took a number of steps. First, Clinton personally took a more active role in the peace-making process, appointing George Mitchell as Special Envoy for Northern Ireland and using an official White House visit to convince Gerry Adams, President of the nationalist Sinn Fein party, to formally join the negotiations. Second, he created an inter-departmental committee to consider economic initiatives and the economic potential of a stable Northern Ireland. Lastly, he offered assistance in drafting the specific terms of the GFA itself.

Members of Congress and President-elect Biden have also voiced their concerns about the Brexit negotiations. Biden and Speaker of the House Nancy Pelosi have essentially stated that, were the UK to break international law, they will refrain from establishing a US-UK trade deal (Mason, 2020; Martin, 2020). In the U.S., the power to negotiate trade deals is under the president’s purview, however such agreements must pass through both legislative chambers to become a reality. Prior to this election, President Trump may not have voiced concerns over the issue at hand simply because of the chance that the US would benefit from a new trade deal. However, with the Democrats holding a majority in the lower house, they have been able to use their leverage to maintain other trade agreements on Trump’s chopping block. Since the beginning of the Brexit process, the UK Conservative government has promised that it would secure a trade deal which would be beneficial for the country for different reasons. First, the UK cannot necessarily ‘strike out on its own’ due to its size and access to resources. Current US-UK trade is worth £221bn, or 20% of the UK’s exports, and the government suggests a new trade deal could increase that number by £15.8bn (Office of the United States Trade Representative, 2020; Borger & O’Carroll, 2020). Other benefits include increases in real wages, maximisation of the UK’s global reach in certain sectors, removal of trade barriers and tariffs, and further bolstering of markets and services that already exist within the UK.

As a guarantor of the treaty, the US is sending similar Protective and Warning Signals to that of the EU. First, America is seemingly reaffirming its commitment to democracy and existing treaties after four years of Donald Trump encroaching on democratic norms and withdrawing from international commitments. With the prospect of the UK government breaking international law to ensure Brexit occurs, the US is calling into question its overall trustworthiness in the global arena and as a potential political and economic partner. Moreover, the US is signalling to Northern Ireland that it is willing to use its influence and economic leverage over the UK to keep the Good Friday Agreement intact.


Overall, the Good Friday Agreement established peace and prosperity in the wake of continued conflict in Northern Ireland and the Republic. As the withdrawal agreement deadline quickly approaches, concerns have been raised about whether or not the UK government will maintain initial commitments of protecting the GFA, particularly as it threatens to break international agreements. However, this is problematic, since imposing a hard border in Northern Ireland would risk escalating the terror threat posed by dissident republican groups (Dearden, 2020). While both the EU and the US have incentives to maintain the GFA and have signalled concerns, sustained pressure is necessary to ensure that the agreement remains intact. This is vital, as the protective and warning signals that the EU gives might quell separatist movements in other parts of the Union, and strengthen European solidarity in the face of an increasingly powerful China and Russia.





Behr, R. (2020) Boris Johnson’s Brexit has always been a swindle. Now Ireland will pay the price. The Guardian, 15 September. Available at: [Accessed 10/11/2020].

Borger, J., O’Carroll, L. (2020) UK plans to change Brexit rules threaten US trade deal, top Democrats say. The Guardian, 09 September. Available at:  [Accessed 10/11/2020].

Byrne, M. (2016) The Principle of Recognition: the people, the state universality and the Good Friday Agreement. Irish Journal of Sociology, 24(3), pp. 255-271.

Center Forward. (2019) US Involvement in the Northern Irish Peace Process and the Good Friday Agreement. Center Forward. Available at: [Accessed 30/10/2020]

Dearden, L. (2020) Hard border in Northern Ireland would become terror attack target, government warned. The Independent, 05 October. Available at: [Accessed 21/11/2020].

European Commission. (2020a) Single Market European Union. Available at: [Accessed 1 December 2020].

European Commission. (2020b) The EU-UK Withdrawal Agreement. European Commission. Available at:  [Accessed 10/11/2020].

Elgot, J., Syal, R., Boffey, D. (2020) Senior Tories urge ministers to scrap ‘illegal’ Brexit rule plan. The Guardian, 08 September. Available at: [Accessed 10/11/2020].

Farry, S., Eastwood, S. (2020) Good Friday Agreement: why it matters in Brexit. UK in a changing Europe. Available at: [Accessed 10/11/2020].

Fung, B. (2019) The British are frantically Googling what the E.U. is, hours after voting to leave it. The Washington Post. Available at: [Accessed 10/11/2020].

Hayward, K. (2019) Johnson’s unworkable Brexit plan won’t solve the Northern Ireland border issue. The Guardian, 03 October. Available at: [Accessed 10/11/2020].

Henley, J. (2016) Why referendums are problematic – yet more popular than ever. The Guardian, 06 October. Available at: [Accessed 10/11/2020].

Henley, J., Carroll, R., Rice-Oxley, M. (2019) Referendums: who holds them, why, and are they always a dog’s Brexit? The Guardian, 11 March. Available at: [Accessed 10/11/2020].

HM Government. (2019) Agreement on the withdrawal of the United Kingdom of Great Britain and Northern Ireland from the European Union and the European Atomic Energy Community. Available at: [Accessed 30/11/20].

Martin, E., Bloomberg. (2020) Pelosi to Britain: ‘No chance’ of a U.S. trade deal if you jeopardize the Good Friday accord. Fortune, 10 September. Available at:  [Accessed 10/11/2020].

Mason, A. (2020) What does a Biden Presidency Mean for Europe? International Development Research Network, 20 November. Available at: [Accessed 02/12/20].

O’Carroll, L. (2020) Key points: what the UK wants in a US trade deal. The Guardian, 02 March. Available at: [Accessed 30/11/2020].

Office of the United States Trade Representative. (2020) United Kingdom. Available at:,was%20%2421.8%20billion%20in%202019. [Accessed 01/12/2020].

Parker, G. (2020) Joe Biden warns Boris Johnson not to let Brexit upend Northern Ireland peace process. Financial Times, 10 November. Available at: [Accessed 30/11/2020].

Staff, T.W. (2020) Brexit: what are the pros and cons of leaving the EU? The Week UK, 06 October. Available at: [Accessed 25/11/2020].

Truss, E. (2020) The U.K. Wants a U.S. Trade Deal. The Wall Street Journal, 01 March. Available at:  [Accessed 25/11/2020].

Wincott, D. (2017) Brexit dilemmas: New opportunities and tough choices in unsettled times. The British Journal of Politics and International Relations, 19(4), pp. 680-695.

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Recommended citation:

Sweezy, A., Yeandle, A. (2020) Brexit and the Good Friday Agreement – An Explainer, IDRN, 03 December. Available at: [Accessed dd/mm/yyyy].