The DUP’s failure in the British parliament is almost beyond caricature. Theresa May’s calamitous failure to win a majority in the 2017 election gave the party a unique opportunity to establish itself as a serious power broker in British politics. Instead a mixture of hubris, lack of strategic foresight and sleaziness verging on corruption has seen it become the fall guy.

Its first mistake was to support Brexit without thinking through the economic consequences for Northern Ireland, including its rural support base.

The second was to double down on that choice by not only choosing to prioritise east-west trade over North-South, but to do so in the face of majority opinion in Northern Ireland. The result has been not just a radicalisation of nationalism, but alienation of both the political centre and the business community.

The third mistake flowed from that. The DUP quite deliberately tried to extend the principle of consent underlying the Belfast Agreement to demand the power to veto any deal made with Brussels. This was part of a broader attempt to widen the concept of “parallel consent” to mean that, in essence, nothing can happen in Northern Ireland unless it agrees. It proved a classic case of over-reach.

Coup de grace

The first hint came when Westminster voted to change the law in Northern Ireland on same-sex marriage and abortion, against the explicit wishes of the party. The coup de grace was the prime minister’s deal with the Taoiseach on North-South trade. The DUP’s one-sided, belligerent stance and failure to engage with other parties meant that their legitimate questions about the impact on east-west trade weren’t heard or taken seriously.

And there is one other factor: sleaze. Whether it was Ian Paisley Jnr’s paid-for “holidays” or the Renewable Heat Incentive (RHI) energy scandal, there are now serious question marks over DUP ethics.

As Sam McBride in his book Burned has chronicled meticulously, the small, inward nature of the leadership, plus the party’s ability to rely on a sectarian head-count, has bred a lack of accountability which is beginning to become all too obvious.

And meanwhile, all Sinn Féin have had to do is sit back and watch – and that is all they have done. And that too is a failure.

There is also a fundamental flaw, not so much in the Belfast Agreement itself as in its implementation

By turning the 19th-century boycott tactic into a 21st-century principle of abstentionism, they left the stage empty for the DUP to fill the vacuum at Westminster. Not only did the party miss out on a platform to argue against Brexit, they also flunked the chance to reach beyond their support base and put themselves at the head of a pluralistic majority in the North of nationalists and non-nationalists. The implications for any united Ireland campaign are obvious.

Majority opinion

Instead the Taoiseach, for the first time in my political memory, has become the voice for majority opinion in Northern Ireland.

But, if we are being honest, there has been one other failure in this period: that of the agreement signed in Belfast on Good Friday 1998.

Stormont remains closed, shuttered not so much by the difficulty of the issues on the table as by a lack of political will to close the gap. Part of the reason for that no doubt comes down to leadership and personality issues, but there is also a fundamental flaw, not so much in the agreement itself as in its implementation, which needs to be both recognised and addressed.

When the Belfast Agreement was signed, the Ulster Unionist Party and the SDLP were dominant, and the assumption was that, whilst they would disagree over many things, they would see the need to compromise for the greater good. But the DUP and Sinn Féin are now dominant, and they have regressed to seeing politics as simply the conflict transferred to a different arena – the zero sum game.

The latest social attitudes survey suggests half of Northern Ireland’s population now self-identify as non-aligned

And Stormont’s rules – particularly the petition of concern procedure – has fed that polarisation and, with it, the failure to establish “normal” politics. What was meant to be an emergency handbrake to prevent the abuse of legitimate rights has been turned into a way for the two parties to block any measure they don’t like, completely at odds with the spirit of the agreement. Any incentive to compromise is gone.

Grasp the nettle

An election would present the centre ground with an opportunity to reverse that dynamic, but to do so it has to persuade the electorate that because in the last 21 years the political context in Northern Ireland has changed, it is time to grasp the nettle and change the way the agreement is implemented. The zero sum game, as represented by the petition of concern, has to go. No one community should be able to block change.

Because Northern Ireland is no longer made up of two communities, and two traditions. There are now three: unionist, nationalist and non-aligned. And the third category is growing. The latest social attitudes survey suggests half of Northern Ireland’s population now self-identify as non-aligned. Twenty per cent voted for parties of the centre at the European elections in June.

And yet, at present, under the way the agreement is being implemented, their voice is not heard. Instead the DUP and Sinn Féin have, in effect, a veto on progress, even if there is a clear majority in the Assembly including the non-aligned centre. But if the rules around sufficient consensus were changed to recognise the growing significance of the non-aligned vote, then not only would that be more representative of the reality of 2019 rather than 1998, it would also force the DUP and Sinn Féin to seek centre ground support through compromise.

But that will only happen if the centre ground continues its upward trajectory at the ballot box. It is not too much to say that the future of the Belfast Agreement depends on it.

Tom Kelly was an adviser in the Northern Ireland Office (1998-2001) and No 10 Downing Street (2001-2007) where he was the prime minister’s official spokesman