The Sinn Fein President was speaking at The National Press Club in Washington DC when she told the audience it’s time for Northern Ireland and the Republic of Ireland to become one again.
“We are coming to a point now, we believe over the next five to 10 years where we will make a decision in respect of the constitutional future of Ireland,” she said.
“In other words we are facing into the holding of referendums north and south in which the question will be put around the removal of the border and the ending of partition, the reunification of our island.
“The island as you know is partitioned a century this year. So we are 100 years on and we are now on the threshold of writing the next chapter of Irish history.”
Mary Lou said that she has raised the issue of Irish unification with both representatives in the Dail, and the American administration.
“I have raised with our own government in Dublin but also with the American administration the absolute urgency and need to begin preparations now for that constitutional transition.
“So I can be very clear on this matter. What I wish to see and what I envisage is an orderly, organised, democratic and peaceful transition to an reunified Ireland.
“I believe that we can do that. I believe that the opportunities that we face as an Island, as a people, once divided but that will be so much stronger when united, our opportunities are immense. I think this is a moment of great optimism and excitement for Ireland.
“I don't believe that anybody should come to the reunification debate with a heavy heart or a sense of foreboding, but with an eye on the big prize, an eye on the win for everyone.”
Mary Lou travelled to the United States this week over concerns that the British government may “breach international agreements” relating to both Brexit and The Troubles in Northern Ireland.
Her speech in Washington came after she met with US politicians in New York amid concerns that the British Prime Minister Boris Johnson could override parts of his Brexit deal with the EU by triggering Article 16 of Northern Ireland protocol, something he has branded as “perfectly legitimate.”
Article 16 of the protocol is a “safeguard clause'' within the Northern Ireland Protocol that allows either party to take unilateral "strictly necessary" measures if applying the protocol "leads to serious economic, societal or environmental difficulties that are liable to persist, or to diversion of trade".
Mary Lou’s party are also concerned that the British government may breach the 2014 Stormont House Agreement if it proceeds to give amnesty to those accused of crimes during the Troubles.
In an address to the New York Bar Association on Thursday, Mary Lou said that it was encouraging that the US continued to be so engaged with Ireland.
The party leader received two standing ovations for her presentation, and told attendees she would challenge and not accept any suggestion that Irish unity would lead to violence.
She also described Brexit as “the outworking of Britain in denial,” adding “[it’s] a product of narrow English nationalism and a hankering for the days of Empire”
“The Good Friday agreement was never the end point, it was never a final constitutional settlement. It is a framework, a set of rules for managing political differences today and tomorrow.”
“It asserts the primacy of politics over conflict. The rights of all over the interests of the few. That is why agreements made must be delivered. Anything less undermines the political process,” she said, proceeding to explain that when the US talks, the UK listens.
“That is why the voice of the US is so important. When Washington talks, Westminster listens. President Biden made this crystal clear when he issued a formal diplomatic rebuke to Britain for failing to honour their agreement.”