Some observers fear that the UK’s impending departure from the EU threatens the Good Friday Agreement; they include Tony Blair, the UK prime minister who presided over the accord. Ireland’s prime minister, Leo Varadkar,
echoed this point in March 2018, arguing that Brexit “threatens to drive a wedge between Britain and Ireland, between Northern Ireland and the Republic of Ireland, and potentially between the two communities in Northern Ireland.” Sinn Fein leaders
have called Brexit “
the most serious threat in the history of the peace process.”