A trade deal with the United Kingdom is "desirable", but anything that endangers the Northern Ireland peace process would stop it happening, said a key United States congressman.
The Good Friday agreement of 1998 ended decades of violent conflict on the island of Ireland, which frequently spilled over into the British mainland and beyond, claiming thousands of lives.
It eased tensions and removed the hard border between Northern Ireland, which is politically part of the UK despite being geographically separate, and the Republic of Ireland.
Speaking ahead of the agreement's 24th anniversary, US Congressman Richard Neal, chairman of the ways and means committee that writes trade deals, told The Guardian: "We will not entertain a trade agreement if there is any jeopardy to the Good Friday agreement.
"A bilateral trade agreement with the UK is desirable－there's no question about that …but what I'm not open to is holding the Good Friday agreement hostage over domestic politics."
A free-trade deal with the US was one of the main pledges of the Leave campaign in the 2016 referendum on Britain's future in or out of the European Union, with former US president Donald Trump repeatedly promising a deal.
"I think we'll make a fantastic and big trade deal with the UK.That's moving along rapidly," he said in August 2019.
"Britain and the US will now be free to strike a massive new trade deal after Brexit … (it) has the potential to be far bigger and more lucrative than any deal that could be made with the EU," Trump said again the following January.
However, no deal happened. And with Trump's successor Joe Biden looking more favorably on Europe, particularly in light of the Ukraine conflict, Britain is now believed to be more keen than ever to strengthen trans-Atlantic ties.
But the post-Brexit status of Northern Ireland remains as significant a stumbling block in dealing with Washington as it does in dealing with Brussels.
To avoid the reintroduction of a hard border with the Republic of Ireland, undoing years of slow delicate progress, a halfway house arrangement for Northern Ireland, called the Northern Ireland Protocol, was devised in the Brexit agreement with some EU regulations still being enforced.
Some people in the North feel they are being treated as unequal British citizens, and some British politicians who agreed to it now want to rip it up.
Such is the importance of the Irish lobby in US politics that senior figures, including US President Biden, said it takes priority over any possible trade deal, a point reiterated by Neal.
"We are concerned that the protocol is being used to hold the Good Friday agreement hostage," Neal said. "The argument being applied by some is reckless and demagogic."
