For a Brexit-minded MP, the parallels may seem striking: an electorally embattled prime minister trying to push through a controversial Northern Ireland deal in the face of Tory and Democratic Unionist party (DUP) scepticism. But one thing has changed: this is 2023, not 2019. Theresa May’s struggles with Brexit, and her tumbling popularity with voters, led to her being forced out as prime minister by Conservative backbenchers. While no one would dispute that Rishi Sunak faces perhaps his toughest ever political test, the stakes for him are if not necessarily lower then perhaps different. The prime minister is widely expected to unveil his revised plan for Northern Ireland’s post-Brexit trading arrangements on Monday. He will do so in a world in which many voters rarely think about relations with the EU, and even less about red and green trade lanes or the scope of the European court of justice (ECJ). When May was struggling with her doomed Brexit votes, a full two-thirds of British voters considered departure from the EU the most important issue facing the country. That figure is now between about 15% and 20%. This does not necessarily make it any easier for Sunak – who will hold final talks with the European Commission head, Ursula von der Leyen, on Monday – to create a fudge sufficiently deep and thick enough to submerge the inherent Brexit contradiction of avoiding trade borders on the island of Ireland and in the Irish Sea. It does, however, create a notably different political landscape for Sunak’s two main stumbling blocks to getting his deal finalised: the DUP and the European Research Group (ERG). Mark Francois, who chairs the ERG, a collection of Brexit-minded Conservative backbenchers, was adamant on Sunday that a plan involving any ECJ role would be unacceptable. But others in the organisation have laid low or said they cannot pass comment before viewing the legal text. More widely in the Conservative parliamentary party, Brexit purism is viewed as not just a niche pursuit but one that could derail a rare and notable political victory for Sunak, one they fervently hope could turn around polling that currently points towards their imminent unemployment. British politics is seemingly beyond the point of “peak ERG”, said Tim Bale, a professor of politics at Queen Mary University of London. He said: “They’re by no means a completely spent force but they are a reduced one. No surrender on the Northern Ireland issue would be nice, but there are relatively few Brexit ultras who regard it as existential in the way that they saw both the withdrawal and the trade and cooperation agreements as existential.” Some of those planning to make a stand, Bale added, mainly hope to damage Sunak and restore Boris Johnson, in the hope that he could change the electoral arithmetic. “Most of their colleagues, however, seem to have concluded that it’s probably Rishi or bust now and that voters, even leave voters, don’t really understand or care about Northern Ireland,” he added. That said, if the DUP explicitly disowns Sunak’s deal, many Tory MPs would feel obliged to follow suit. The unionist party remains officially undecided but is very clearly annoyed at what it sees as a lack of No 10 consultation. The election picture in Northern Ireland is more complex. Polling there shows almost half of voters see the protocol as a long way down their list of priorities, but for a core of about 20% it remains the top priority. This group are overwhelmingly unionist, thus essential to DUP electoral prospects. The DUP, Bale said, are “probably less worried about being seen as dinosaurs than sellouts – they’re more vulnerable to losing support to hardline unionist than to floating voters”. As ever with Brexit, it is a hugely complex issue with many moving parts. And as it was with May, perhaps the best advice for Sunak would be that most useless of political mantras: maybe don’t start from here.