LEICESTER, United Kingdom – Northern Ireland’s Catholic bishops have sent a letter to world leaders including Nancy Pelosi and the U.S. special envoy for Northern Ireland to urge them to use their influence to make sure the Good Friday Agreement isn’t a casualty of Brexit.

The United States played a key role in facilitating the 1998 Agreement that ended the “Troubles” in Northern Ireland that left over 3,500 people dead.

The first U.S. special envoy for Northern Ireland was former Senator George Mitchell, who was appointed in 1995 and ended up chairing the talks that led to the Agreement, having previously headed the international commission on disarmament of paramilitary groups. The current envoy is Mick Mulvaney, appointed by President Donald Trump.

The agreement was undergirded by the fact that both the UK and the Republic of Ireland were members of the European Union, and the Common Market eased the removal of all border controls on the island of Ireland that was a key feature of the accord.

With the UK leaving the EU in January, the Irish border has become an issue as the two sides negotiate their final deal when a transition period ends at the end of the year.

The Northern Irish bishops called the Good Friday Agreement “the vital cornerstone of progress towards peace in Northern Ireland,” and warned a “hard border” on the island of Ireland would put that peace in jeopardy.

“The UK and Irish governments, as signatories of this Agreement, must both ensure, along with friends and supporters in Europe, the US and globally, that a Brexit deal is formulated around the provisions of this Agreement, not contrary to them. Any deal which changes the effects, content or spirit of the Good Friday/Belfast Agreement cannot be accepted on this island where people voted overwhelmingly to endorse this Agreement as the foundational basis for our shared and reconciled future,” the bishops said in the Oct. 8 letter.

The UK and EU had agreed that no border infrastructure would be implemented on Ireland, but British Prime Minister Boris Johnson’s government has since announced it was willing to violate the withdrawal agreement – and thereby break international law – to ensure no trade barriers are put between Northern Ireland and the rest of the UK.

The bishops said that a return to any border apparatus on this island, even if only for customs and trade checks, “would be a dangerous backward step.”

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“It would inevitably threaten the fragile peace and political stability towards which substantial strides have been made since the Good Friday/Belfast Agreement. The removal of border structures on this island has been of significant benefit to the daily lives of families, communities and businesses in border regions, but most importantly, it has been crucial to the functioning of the Good Friday/Belfast Agreement, to the step-by-step growth in normality in our society, and to the maintenance of peace,” their letter said.

The bishops warned that despite its many achievements as a model of peacebuilding and reconciliation, Northern Ireland remains a post-conflict society facing many challenges.

“These include ensuring a compassionate and just response for those most directly affected by the violence of the past, dealing with the painful and traumatic legacy of division, tackling continued paramilitary activity and sectarianism, and restructuring the economy to create a sustainable future for our society,” their letter said. “At present, the economy is fragile and heavily dependent on public services, while many in our society are already marginalised and living in poverty, including many young people. The COVID-19 pandemic has brought additional challenges and its far-reaching, and often devastating, effects on our society and economy are still emerging.”

The bishops also asked all parties to recognize the “unique identity” of Northern Ireland, which “cannot be reduced to a binary alternative.”

“Its unique position was recognised in the Good Friday/Belfast Agreement which provides that there are three important strands to its identity, including intra-community relations, relations between North and South on the island and between East and West on these islands,” referring to Ireland and Great Britain.

“In fact, ever more we need to realize its exceptionalism as the important strands intrinsic to its identity have expanded beyond the three key relationships, to another strong bond with Europe,” the bishops said, noting that a majority (56 percent) of Northern Ireland voted to remain in the EU during the Brexit referendum.

“At this decisive time, we are urging the international community – which contributed so much on both sides of the Atlantic to the achievement of our peace process – to use the influence and diplomatic leverage they have in trade and other negotiations surrounding Brexit to ensure that the Good Friday/Belfast Agreement is respected and to avoid any return to a hard border on the island of Ireland,” the bishops’ letter said.

The Trump administration has said it “trusts” the UK to uphold its obligations under the Good Friday Agreement.

However, Mulvaney said last week it is “central” to the peace process and the U.S. was “concerned” about the impact of Brexit negotiations on the Irish border.

“It’s really through the prism of the Good Friday Agreement that we watch that because that’s where we are so heavily invested … that’s the one that we really have so much blood sweat and tears in,” he said, according to the Independent.

Pelosi had already declared on Sept. 9 that the U.S. Congress won’t tolerate a violation of the Agreement.

“If the UK violates that international treaty and Brexit undermines the Good Friday accord, there will be absolutely no chance of a U.S.-UK trade agreement passing the Congress,” Pelosi said

Presidential candidate Joe Biden has already signaled his opposition to any changes to the peace deal.

“We can’t allow the Good Friday Agreement that brought peace to Northern Ireland to become a casualty of Brexit,” Biden tweeted on Sept. 17. “Any trade deal between the U.S. and U.K. must be contingent upon respect for the Agreement and preventing the return of a hard border. Period.”

Follow Charles Collins on Twitter: @CharlesinRome