Shortly after arriving in Dublin, President Trump said it would be "fantastic" if Northern Ireland and the Republic of Ireland unified, breaking with decades of U.S. neutrality. Speaking alongside Taoiseach Micheál Martin, Trump said unification was "going to happen eventually," then acknowledged the politically sensitive topic by joking half the room would clear out. The U.S. has long supported the 1998 Belfast Agreement, which ended roughly three decades of violence and stipulated Northern Ireland remains in the U.K. unless a majority votes otherwise in a referendum.

Trump had earlier mused about a "merger" and praised Northern Ireland's deputy first minister Emma Little-Pengelly's rapport with Martin. British Prime Minister Andy Burnham responded that there is not enough public support for a referendum. Gavin Robinson, leader of Northern Ireland's main pro-union party, said the region's constitutional future would be decided by its people.

Trump also attacked Democrats, including describing former President Joseph R. Biden Jr., who has cancer, as physically infirm.