Former US special envoy for Northern Ireland George Mitchell has said that the return of a hard Border on the island of Ireland after Brexit would be "extraordinarily harmful".
He also said he believed the British vote to leave the EU will “prove historically to be a huge error”.
The former US senator made the comments on Thursday during a visit to Ballina, Co Mayo, to deliver this year's Mary Robinson Centre International Human Rights lecture.
Mr Mitchell said that while he respected the decision of the British electorate in last June’s EU membership referendum, he was concerned at the implications of the vote.
"A less stable Europe. is harmful to the US as one of its major trading partners," he said.
However, he also said the EU’s institutions must be improved and its bureaucracy reduced,“just like barnacles at the bottom of a ship”.
Mr Mitchell, who was central to the negotiations which led to the Belfast Agreement in 1998, said he had spoken to Northern Secretary James Brokenshire about his Brexit concerns, and discussed the issue with Taoiseach Enda Kenny on Wednesday.
He said the absence of a physical Border in Ireland had played an enormous role in improving trade, breaking down barriers and reducing “stereotyping and demonisation” on the island.
“I hope the US government will support and work with the Irish Government and leaders of the EU to achieve an outcome that respects the gains made in recent years,” he said.
Mr Mitchell said he did not believe that the tax reforms announced by the Trump administration on Wednesday would be implemented as outlined, because the US Congress was not committed to the president’s agenda.
However, he said he supported US tax reform, especially in relation to corporate tax , as the American model was outdated and a “disincentive” to growth.
Any corporate tax reforms were not necessarily a challenge for Ireland because US companies value the quality and skills of Irish staff, he said.
During his lecture at St Patrick’s church, Mr Mitchell said that the network of alliances among free nations that had developed since the second World War must be renewed and reinvigorated to meet the challenges of the 21st-century.
He said trade agreements and institutions, in spite of their flaws, had brought peace and stability to Europe in the aftermath of two World Wars.
Challenges
Mr Mitchell described the three great challenges to peace in the 21st-century as globalisation and rapid technological change, climate change, and rapid population growth in the least-developed areas.
During times of transition and disorientation in history, such as the industrial revolution, there was widespread fear and anxiety, violence, and exploitation, he said.
Today’s technological revolution is as significant as the industrial revolution, he added.
It has led to the creation of a level of wealth that is “without precedent in history”, but which is not being distributed throughout society.
As a result, many millions of people were victims, rather than beneficiaries, of this revolution, he said.
Mr Mitchell said science and innovation must not be stifled or rejected, while good health, education and relevant 21st-century skills should be made available to all.
In a discussion with Mary Robinson that was moderated by journalist Olivia O'Leary, Mr Mitchell said he thought it "unlikely" that Donald Trump would be able to carry through on his campaign pledge to withdraw from the Paris agreement on climate change.
He also said the US Environmental Protection Agency would encounter difficulty in avoiding its commitments in this regard.
Mr Mitchell noted that Mr Trump had reversed his positions on China and on Nato, but said he was concerned that the US president had not retracted his pre-election statements on developing nuclear weapons.
The US had pushed for the non-proliferation of nuclear weapons with “remarkable success”, and a reversal of this position could lead to nuclear weapons falling into the hands of terrorist groups who have “no borders, and therefore no fear of retaliation”, Mr Mitchell said.
