The next stages of Brexit are now set to happen under a new Prime Minister. The chosen candidate will have to work with governments in Wales and Scotland that are openly critical. Northern Ireland may be without a government and the English regions may lack a unified voice, but neither can be taken for granted, especially as the new PM will rely on the DUP for confidence and supply. Leaving the European Union therefore cannot be separated from the challenges of maintaining the domestic union, as Jack Sheldon explains.

Following the announcement of Theresa May’s imminent resignation, the long-anticipated contest within the Conservative Party to succeed her has begun.

The campaign will inevitably be dominated by Brexit. But events over the past three years have shown that the future of relations with the EU cannot easily be separated from the future of the domestic Union. The candidates will thus need to give careful thought to how they will approach the major statecraft challenges presented by territorial politics across the UK if they become Prime Minister.

Renegotiating the Northern Ireland backstop will be popular with Conservative MPs – but a new Prime Minister might soon face the same dilemma as Theresa May

The Northern Ireland ‘backstop’ has been the main driver of opposition to the Withdrawal Agreement within the parliamentary Conservative Party and their confidence-and-supply partners the DUP. Consequently, there are strong short-term incentives for leadership contenders to commit to renegotiating it, in the hope that it might yet be possible to get a deal that doesn’t cut across Brexiteer red lines on the Single Market and customs union through the House of Commons. Pledges to this effect have already been made by Jeremy Hunt, Boris Johnson, Esther McVey and Dominic Raab.

In reality, substantive changes to the backstop will be extremely difficult to deliver. It remains the position of the EU27 and the Irish government that the Withdrawal Agreement will not be reopened.  Keeping an open Irish border has become highly salient in Ireland and the EU, and the new Prime Minister will need to appreciate that this means there is next to no chance that they will be open to trading the guarantees provided by the backstop for the loosely-defined ‘alternative arrangements’ envisaged by many Conservative MPs. The same dilemma Theresa May faced might thus soon confront her successor – whether, as an avowed unionist, to recoil from a no-deal scenario that would undoubtedly have disruptive effects at the Irish border and strengthen the case for an Irish border poll, or whether the delivery of Brexit trumps everything else.