Dismay after Pence backs Brexiteers over Ireland
The White House has opened up a new front in the Brexit battle, suggesting Ireland and the EU have been disingenuous in negotiations.
Despite being feted on a visit to Dublin, US Vice President Mike Pence used an appearance alongside the Taoiseach to effectively back UK Prime Minister Boris Johnson's hardline opposition on the backstop.
"As the deadline for Brexit approaches we urge Ireland, and the EU as well, to negotiate in good faith with Prime Minister Johnson," he said.
He asked that they "work to reach an agreement that respects the UK's sovereignty and minimises disruption to commerce".
The Trump administration has long been a supporter of Brexit - but there was still surprise Mr Pence would issue such a strident statement while in the company of Leo Varadkar.
He was speaking just moments after the Taoiseach had asked him to bring an understanding of the Good Friday Agreement and the backstop back to Washington.
The return of a hard Border was described as a "very real risk" by Mr Varadkar. He said Brexit could create barriers to North-south co-operation and risk peace.
"We as a Government have to stand our ground on the agreement," he said. "All I ask is that you bring that message back to Washington with you.
"This is not a problem of our making.
"It is one we want to solve through an orderly Brexit and a Withdrawal Agreement that guarantees no re-emergence of a hard Border on this island."
Sources say the Taoiseach repeatedly explained Ireland's attachment to the backstop during a private 30-minute meeting with Mr Pence.
One official told the Irish Independent Mr Pence appeared to have a "good understanding" of the issues and the Government's "commitment to the Good Friday Agreement".
But separate Government sources admitted the comments by Mr Pence were not what they would have hoped for under the circumstances.
Mr Pence did acknowledge the "unique challenges on your northern border", saying he would encourage the UK and Ireland to ensure that any Brexit deal respects the agreement.
However, he quickly moved on to promise that the US would strike a trade deal with the UK once they are outside the EU.
This is a controversial topic in the US where a number of high-profile Irish American politicians are threatening to block a deal if Brexit causes any damage to the Good Friday Agreement.
Among those who have publicly committed to stalling a trade deal is House Speaker Nancy Pelosi.
In a statement last month, she said: "If Brexit undermines the Good Friday accord, there will be no chance of a US-UK trade agreement passing the Congress.
"The peace of the Good Friday Agreement is treasured by the American people and will be fiercely defended on a bi-cameral and bi-partisan basis in the United States Congress."
While Brexit dominated their private meeting, Mr Pence also wanted to emphasis the US's objection to the use of products manufactured by Huawei.