Speaking as voting on whether to rule out a no-deal Brexit began at Westminster, Mr Varadkar said: "It's always important to remind ourselves that Brexit.is the decision that the United Kingdom has made, a decision that we deeply regret in Ireland and across Europe".
Irish Prime Minister Leo Varadkar arrived in Washington this week as part of an annual trip ahead of St Patrick's Day.
He was surprised how badly the Brexit talks had gone, adding: "I gave the prime minister [Mrs May] my ideas on how to negotiate. she didn't listen to that and that's fine".
Trump's intervention on Brexit is very welcome, according to pro-Brexit analyst Niles Gardiner, who worked for former British Prime Minister Margaret Thatcher after she left office. "I regret Brexit's happening". "There is every expectation in Washington that a USA -U.K. trade deal could be in place by the end of 2019 if Brexit goes forward this month and Britain successfully leaves the Customs Union".More news: Five dead, 36 injured in foot bridge collapse in Mumbai
Britain is set to exit the European Union on March 29, but lawmakers voted Thursday to allow the government to seek a delay to the Brexit date.
Until the 1998 Good Friday agreement, violence in the previous three decades in Northern Ireland killed more than 3,500 people.
"I think it could've been negotiated in a different manner, frankly".
In his speech, Mr Varadkar said: "Your ambition is to "Make America Great Again", and I think we can already see some of the results of that".More news: Police responding to reported mass shooting in New Zealand
The exchange of views Trump is referring to took place in a meeting last summer, with May later saying that his advice was to sue the EU.
Gardiner rejects Irish concerns about the border and said the issue has been used as a "battering ram" by European Union leadership keen to make Britain a cautionary example to other member states flirting with an exit. Pence attempted the Irish leader's formal title, calling him "Taoiseach Varadkar".
Speaking to Ireland's RTE News on Wednesday, Varadkar confirmed that his partner would attend the traditional breakfast with Pence.
"The United States and the Republic of Ireland have such close ties that it's unlikely that anything permanently damaging would happen", McMahon said.More news: London confirmed as World Series sevens venue for next four years
Trump may agree. At the luncheon, he sounded cheerful as he described his discussion with Varadkar. He said: "If they don't talk to us, we're going to do something pretty severe economically". "One way or the other it's going to work out".