The agreement was for Northern Ireland to be part of the United Kingdom and remain in place until a majority of the population of Northern Ireland and the Republic of Ireland wished otherwise. If this happens, the British and Irish governments will be “obliged” to implement this decision. The agreement was approved by voters across the island of Ireland in two referendums on 22 May 1998. In Northern Ireland, in the 1998 referendum on the Good Friday Agreement in Northern Ireland, voters were asked if they supported the multi-party agreement. In the Republic of Ireland, voters were asked whether they would allow the state to sign the agreement and authorize the necessary constitutional changes (nineteen constitutional amendments from Ireland) to facilitate it. The citizens of both countries had to approve the agreement to implement it. These institutional provisions, established in these three areas of action, are defined in the agreement as “interdependent and interdependent”. In particular, it is found that the functioning of the Northern Ireland Assembly and the North-South Council of Ministers is “so closely linked that the success of individual countries depends on that of the other” and that participation in the North-South Council of Ministers “is one of the essential tasks assigned to the relevant bodies in Northern Ireland and the Republic of Ireland]. During negotiations on the UK`s planned withdrawal from the European Union in 2019, the EU presented a position paper on its concerns about Britain`s support for the Good Friday agreement during Brexit. The position paper deals with issues such as the prevention of a hard border, north-south cooperation between the Republic of Northern Ireland, the birthright of all Northern Ireland residents (as stated in the agreement) and the common travel area.   Anyone who was born in Northern Ireland and is therefore entitled to an Irish passport under the Good Friday Agreement may retain European citizenship after Brexit.  As part of the EU`s Brexit negotiating guidelines, the UK was asked to convince other EU members that these issues had been addressed in order to enter the second phase of the Brexit negotiations. In order to protect North-South cooperation and avoid controls at the Irish border, the United Kingdom, under the leadership of Prime Minister Theresa May, agreed to protect the agreement in all its parts, and “in the absence of agreed solutions, the United Kingdom would maintain full alignment with the rules of the internal market and customs union which, now or in the future, North-South cooperation support the island economy and the protection of the 1998 agreement , acknowledging that “it is the restriction that nothing is agreed until everything has been agreed.”     This provision was part of an agreement between the United Kingdom and the EU, which was rejected three times by the British Parliament.
 May`s successor, Prime Minister Boris Johnson, initially cited the “Irish backstop” that was to be withdrawn from the proposed agreement, but finally accepted it after the negotiation of a new agreement between the UK and the EU on 17 October 2019.   In September 2020, Northern Ireland Secretary Brandon Lewis has informed the House of Commons that the UK government intends to violate international law in a “specific and limited” manner by introducing a new bill that gives the UK government new national powers to circumvent certain international contractual obligations to the EU, as provided for in the Northern Irish Protocol of the Brexit Withdrawal Agreement.  The bill introduced the following day sparked widespread outrage in the United Kingdom and internationally, with the Prime Ministers of Scotland and Wales calling the Conservative government`s proposals to try to take power and cancel decentralisation.   Most parties in Northern Ireland expressed concern about the law, although some members of the Democratic Unionist Party, who had always opposed the Good Friday agreement, welcomed the law.  Prime Minister Michel Martin said that “confidence” in the government`s plan