Taoiseach Leo Varadkar told Democratic leader Nancy Pelosi and members of her US congressional delegation that he knows they will be there to protect the achievements of the Northern Ireland peace process.
Addressing the issue of Brexit on Wednesday at a State dinner for the US House of Representatives speaker and her fellow members of Congress, Mr Varadkar said that the 1998 Belfast Agreement underpinning the peace process was "still unfulfilled" but that the Government was "determined to fulfil it".
The Taoiseach told guests, including Northern Ireland's DUP leader Arlene Foster, sitting a few feet away from him at the event at Dublin Castle's St Patrick's Hall, that "no matter what happens with Brexit, we will do everything we can to prevent the return of a hard Border between Ireland and Northern Ireland".
The Government was backed in this by countries across the EU and “our friends in the United States”, he said.
Guests at the dinner included former taoisigh Enda Kenny and Bertie Ahern, Labour leader Brendan Howlin and Sinn Féin president Mary Lou McDonald.
Earlier, in an address to the Dáil, Ms Pelosi warned that nothing must happen to “imperil” the peace agreement and “the seamless Border”.
Ms Pelosi also repeated her warning that “if the Brexit deal undermines the accord there will be no chance of a US-UK agreement” on trade.
“I say that hopefully, that we will not have to face that reality.”
After addressing the Dáil, Ms Pelosi met President Michael D Higgins at Áras an Uachtaráin, where they discussed Irish-US bilateral relations, the implications of Brexit, and the peace process. They also discussed migration, the experience of migrants and the "undocumented" and the possibility of new E3 visas for the Irish.
The California congresswoman is scheduled to visit the Border between counties Donegal and Derry on Thursday before travelling on to Belfast on Friday.
‘Beacon of hope’
Ms Pelosi told the Dáil that the 1998 peace agreement should be treasured, not only because of what it has meant for the Republic and Northern Ireland but because it had become a beacon of hope for all the world.
She told a full Dáil chamber that “as you face the challenges posed by Brexit, know that the Democrats and Republicans in the House stand with you”.
To sustained applause, she said: “We must ensure that nothing happens in the Brexit discussions that imperils the Good Friday accord, including but not limited to the seamless Border between the Irish Republic and Northern Ireland.”
She said children born in 1998, when the Belfast Agreement was signed, had grown up in peace. “We cannot jeopardise that,” she continued. “We must not and will not allow that progress to be undermined.”
She praised former SDLP leader John Hume and late former Northern Ireland deputy first minister Martin McGuinness.
Ms Pelosi also made reference to a photo she had seen of former UUP leader David Trimble and Mr Hume at a U2 concert in 1998 after the peace agreement had been signed.
She referred to U2's Bono, who with his wife Ali Hewson sat in the distinguished visitors' gallery during her address, as "one of Ireland's most beloved exports", while paying tribute to his music and campaigning work.
Ms Pelosi said she had heard "excellent arguments" for the State to sit on the UN Security Council, as she highlighted the Republic's efforts in 1961 at the UN to push for non-proliferation of nuclear arms.
She also praised the State’s efforts on green technology, adding that both Ireland and the US could do more on climate change and could do so together.
