Since about 2005, the border has been perceived as invisible, with little or no physical infrastructure, as security barriers and checkpoints have been removed due to processes introduced by the Good Friday Agreement (or "Belfast Agreement") signed in 1998.  [b]  This Agreement has both the status of an international treaty between the United Kingdom and the Republic of Ireland (Anglo-Irish Agreement) and an agreement between the Parties in Northern Ireland (Multi-Party Agreement). On 29 march 2017, Prime Minister Theresa May began the two-year Brexit negotiations with a communication under Article 50 of the Treaty on European Union.  In response, the remaining EU countries (EU27) published their negotiation strategy "in phases", which postponed all negotiations on the future relationship with the UK (the "Political Declaration") until a binding withdrawal agreement was reached: Boris Johnson followed May in July 2019 as Conservative leader and British Prime Minister after failing to break the Brexit deadlock, and their withdrawal agreement with the EU was rejected three times in Parliament. The election of Mr Johnson called into question the UK`s exit mode until the next deadline, on 31 October, because, during his campaign for the head of state, he described the withdrawal agreement as a "dead letter" and asked that the backstop be removed from the withdrawal agreement. Brussels and Dublin insisted that the withdrawal agreement not be renegotiated and that the backstop not be removed from the agreement. On 10 October, Johnson and taoiseach Leo Varadkar had "very positive and very promising" talks, which led to a resumption of negotiations and a week later, on 17 October, Johnson and Jean-Claude Juncker announced that they had agreed (subject to ratification) on a new withdrawal agreement replacing the backstop with a new protocol on Northern Ireland and the Republic of Ireland.  In July 2019, Theresa May resigned and Boris Johnson became prime minister, with Boris Johnson saying he wanted to replace the Irish backstop as part of the withdrawal agreement.  On August 19, in a letter to the President of the European Council, the Prime Minister called the agreement "undemocratic and incompatible with the sovereignty of the United Kingdom."  He stressed that it was "incompatible with the final objective desired by the United Kingdom" for its relations with the EU.
Its third reason why the backstop is not acceptable is that it could "weaken" the Good Friday Agreement and the peace process in Northern Ireland. Tusk replied that those who opposed the arrangement without "realistic alternatives" supported the re-establishment of a hard border on the island of Ireland. That`s the reality, "even if they don`t admit it," he added. "The backstop is insurance to avoid a hard border on the island of Ireland, unless you find an alternative," Tusk tweeted.  Irish government sources have argued that "the real purpose of the backstop is to maintain the status quo by guaranteeing free movement and not the hard border on the island of Ireland; which is essential for the GFA. The reality is that Brexit itself is a threat to the GFA.  Speculation about the fate of the law was reinforced by Joe Biden`s victory in the US election. The president-elect was quick to criticise the law when it was first published, warning that the Good Friday peace deal in Northern Ireland "cannot be a victim of Brexit". On 13 November 2018, a modest speech was published in front of the House of Commons calling for the release of the government`s legal advice on the proposed EU Withdrawal Agreement.
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