Trump's comments on a united Ireland may have targeted audience across the Atlantic

When another world leader meets US President Donald Trump the only certainty about what might happen is the uncertainty about what might happen.

This was exactly the case ahead of President Trump's two-day visit to Ireland.

Nobody could have predicted that by the end of the first day, the main global headline would be his desire to see a unified Ireland .

As the shockwaves of his remarks rippled through this island and Great Britain, it was unclear whether this represented a new US administration policy, or an off-the-cuff remark from a president who likes to take questions from reporters, and likes to give answers.

Former Republican Congressman Mick Mulvaney was Trump's special envoy to Northern Ireland in his first term in office.

He cautioned against anyone reading too much into the president's remarks.

"This does not represent a shift in US foreign policy," he said.

"We're still very much committed to the Good Friday Agreement."