In 1983, as a young lad in Loreto convent in Milford, Co Donegal, a border county in Ireland, you had three choices as a football supporter: Liverpool and Celtic, Manchester United and Celtic, or Arsenal and Celtic. I didn’t yet follow an English team, never mind a Scottish one. I was told in no uncertain terms that I’d be supporting Celtic, just like the rest of Donegal.

But I didn’t. I dared to ignore the well-worn “advice” of a bigger, brawnier schoolmate and declared that Aberdeen was my team – the Dons. Willie Millar, Mark McGhee, Gordon Strachan, Jim Leighton – in those days, with Sir Alex Ferguson at the helm, it was a dream team.

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I didn’t get the herd mentality, and I refused to be defined by it. That year the Dons lifted the European Cup Winners’ Cup and Scottish Cup, and the following year they claimed a Scottish League title.

On the one hand, I was backing the winning horse; on the other it was an act of pure stubbornness, even if it wasn’t the most astute, considering the politically charged atmosphere of that time and place.

Twenty years on from the signing of the Good Friday agreement, I’m reminded of how far a little determination goes. Amid the ongoing impasse with the devolved powersharing executive and assembly in Northern Ireland, I would make the case that what is needed is for people – particularly young people and civic leaders – to not only show determination, but to also demand it.

Just as young people are not defined or constrained by their backgrounds, so they should require of politics and of politicians to overcome their different perspectives, to secure the greater good. The Good Friday agreement protects and recognises a diversity of identity – British, Irish, or both. This is a platform for political engagement, on the basis of equality and mutual respect.

Huge numbers of people in their 30s and younger, look on, bewildered, at the continuing impasse in Stormont

Young people who are just of voting age today weren’t even born when the Good Friday agreement was signed. While they are fortunate not to remember the horrors of the Troubles, my experience is that they recognise and value the great prize of peace that was secured in 1998, and they want to see the benefits of the agreement protected and advanced. Huge numbers of people in their 30s and younger look on, bewildered, at the continuing impasse in Stormont. They expect the issues that divide the parties to be resolved, as the greater challenges of the peace process have been addressed through the Good Friday agreement and over the past 20 years. They must not be let down.

This is the people’s peace agreement, endorsed by huge majorities in simultaneous referendums in both Northern Ireland and Ireland on 22 May 1998. With this unassailable democratic foundation, it falls to each generation – and particularly to those of us in politics – to ensure that its promise can be fulfilled.

The second paragraph of the agreement carries as much force today as it did then: “The tragedies of the past have left a deep and profoundly regrettable legacy of suffering. We can best honour them through a fresh start, in which we firmly dedicate ourselves to the achievement of reconciliation, tolerance, and mutual trust.” The last two decades in Northern Ireland have seen ups and downs, but this ambition has become part of the fabric of politics and more indeed of daily life.

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The agreement has also brought a resilience and a confidence to both parts of the island that simply weren’t there in the dark days of the Troubles. I see this particularly in border counties like my own, Donegal.

What we need now is the same dedication that brought the agreement into being, with the courage to reach a workable compromise and get the devolved institutions operating again. Those demands are undoubtedly greater with Brexit, with Northern Ireland likely to be hardest hit by the new reality. But these are challenges that can and must be addressed and overcome.

Reflecting on my own experience, the journey to a more “normal” and productive politics in Northern Ireland has to involve moving beyond defining and limiting issues on the basis of community or background.

In many communities, people are already setting an example for politicians to emulate, including on the difficult issues of language and culture that are at the core of the current debates. Through this, people are living the principles of the Good Friday agreement that have secured the peace, and are the basis of the journey to full reconciliation that must be collectively pursued in next 20 years and beyond.

• Joe McHugh is the Irish government chief whip; minister for the Irish language, the Gaeltacht and the Islands; and the deputy for Donegal