The United Kingdom’s next prime minister may be an even bigger Brexiteer than Boris Johnson.

Liz Truss, the former foreign secretary, has won the Conservative Party’s leadership contest, setting her up to take over as UK prime minister after Johnson announced in July he would resign. Truss defeated Rishi Sunak in a race she was heavily favored to win, largely because she captivated the right-wing base of the Conservative Party, including its Eurosceptic wing.

How Truss achieved that is a somewhat remarkable political story. A former Liberal Democrat and Remain supporter, she fully embraced Brexit after the 2016 referendum, becoming one of its most ardent backers. As foreign secretary in Johnson’s government, she shored up her Brexit credentials with her confrontational stance toward the European Union.

Her reinvention allowed her to ascend to the top of her party, and now the premiership. That rise says a lot about where the UK’s Conservative Party (or Tory Party) is right now: Even though the UK officially broke with Europe, Brexit has also ballooned into an entrenched domestic political and culture war issue. Truss is the embodiment of this, which also says a lot about how she may lead — when it comes to the European Union, and beyond.

Practically, that may mean even thornier relations between the UK and the EU at a time when the United Kingdom and the rest of the continent are dealing with inflation and energy crises and an ongoing war in Ukraine.

“A question that Liz Truss will basically have to face is: How far does she want to escalate with the EU?” said Nicolai von Ondarza, EU/Europe research group leader at the German Institute for International and Security Affairs (SWP). “And for the EU side: How fast and how strong does one want to retaliate?”

As the new British prime minister, Truss does have the opportunity for a reset, and given the economic and political challenges the UK is facing, it might make sense to attempt it. But Brussels, Paris, and Berlin are bracing for a rockier relationship. Because, as a Brexit latecomer, Truss may have even less room to maneuver than the guy she’s replacing.

The convictions of a Brexit convert

In 2016, Liz Truss warned of the perils of Brexit, saying leaving the EU’s single market would mean industries, like food and drink, would face additional costs getting their products to market. In 2022, during her Conservative leadership campaign, she said she was “wrong and I am prepared to admit I was wrong” about her past stance.

And Conservative Party members, whose votes she needed to win the leadership race, believed her. (Even more wild, Sunak, the candidate she defeated, voted Leave.)

Truss is, to borrow a phrase from the tabloids, a “born-again Brexiteer.” She says she believes in Brexit now because “disruption didn’t happen,” even though plenty of indicators show that those disruptions are very much happening.

Truss also used her tenure in government to build her Brexit bona fides. She served as International Trade Secretary in Johnson’s government, the public face of Britain’s post-Brexit efforts to secure trade deals all over the world. In 2021, she took on the high-profile job of foreign secretary, where she took over the post-Brexit portfolio with the EU.

Truss’s appointment last year came with some hope that she might be a bit more pragmatic and less ideological on Brexit. But she largely maintained a hardline approach when dealing with the EU, especially on issues relating to Northern Ireland, the eternal sticking point of Brexit.

Truss was one of the main architects of the Northern Ireland Protocol Bill that, if it becomes law, would unilaterally rewrite sections of the Brexit deal the UK itself negotiated. Truss is committed to seeing that bill through as prime minister, even as the EU and UK are already in a legal battle over the implementation of the deal. During her campaign, Truss has also promised to scratch all remaining EU law by 2023.

As von Ondarza said, “sometimes converts display the strongest faith.”

Kevin Featherstone, a professorial research fellow in the European Institute at the London School of Economics, said that toughness on the EU has transcended actual policy goals and is now a culture war issue. To go after bureaucrats in Brussels is to shore up your populist appeal. Being anti-EU is a vibe, whatever the policy stakes and fallout.

Truss channels the zeal of the party on this and on other key issues of the Tory base: free markets, deregulation, and a disdain for cultural “wokeness.”

“While Boris Johnson was a leading figure in the Brexiteer camp, he had a wider appeal, whereas Liz Truss’s power base is firmly within the hardcore Brexiteer part of the Parliamentary party, but also the wider Tory party — and so she has to be much firmer on the EU, but also on other economic questions,” von Ondarza said.

For that reason, she may not have as much political space to act, and may not have the domestic political capital to tamp down any tensions with the EU. Because Brexit isn’t actually done, and it could further strain EU-UK relations.

With the EU, will Truss have a “Nixon goes to China” moment or a trade war on her hands?

Yes, yes, they said it was done! But Brexit was always going to create new issues as trade and travel between the UK and EU fundamentally changed.

The status of Northern Ireland remains a key source of tension. Just to recap: Northern Ireland is part of the UK, and so left the EU with it. But as part of a Good Friday Agreement, a peace deal that ended decades of sectarian conflict, the border between Northern Ireland and the Republic of Ireland (which is part of the EU) is supposed to remain open and free from physical infrastructure. After Brexit, the UK left the EU institutions and was expected to diverge on trading rules, and so the UK and EU needed to figure out a way to conduct customs checks without undoing the peace deal and upsetting a politically sensitive border.

Johnson ultimately negotiated a Brexit deal that would mean some goods from the United Kingdom bound for Northern Ireland would have to undergo checks before they arrived there, over concerns they might end up in the EU single market. That is a source of tensions for unionists in Northern Ireland (who don’t want much distance between Northern Ireland and the rest of the UK) and for the Conservative government, who say the deal is creating this divide and complicating commerce within the country.

But the EU says the UK isn’t implementing the deal as agreed, and has launched legal proceedings to get them to comply. The UK, meanwhile, with this Northern Ireland Protocol Bill, is threatening to tear up the entire agreement. Truss has also threatened to trigger a formal mechanism within the Brexit deal that can be invoked when “serious economic, societal or environmental difficulties that are liable to persist” come up — something the EU will be forced to respond to, if that happens.

Either way, it’s messy and could get messier, putting the UK and the EU on the path toward a possible trade war, even as the continent is already in crisis because of war and rising costs of food and fuel.

The Brexit deal isn’t perfect, but this escalation is of a political making. The EU has said it’s willing to talk, but within the framework of original protocol; the UK has indicated it wants more radical changes. “This is a problem which has to do with political culture, which is more winning, and less compromise,” said Georg Boomgaarden, German ambassador to the United Kingdom from 2008 to 2013. “But if we let the experts sit down together, have pragmatic and practical solutions for where there is a real problem, most of the problems Truss brought up are no problem at all.”

The question is will the experts sit down — and will Truss give them her blessing to do so? Featherstone and von Ordonza both mentioned the possibility of a “Nixon goes to China” moment, where Truss, bolstered by her win and the full-throated support of the Brexiteers, brokers a deal with the EU, or appoints someone who will, and frames it as a victory over the EU, even if it involves some concessions along the way.

This would be a dream for Berlin and Paris and Brussels, but the “Nixon goes to China” moment may be just that. Experts I spoke to were skeptical that Truss would use domestic political capital on a still-easy target — the EU — especially when the UK is dealing with plenty of crises at home, from inflation to labor strikes.

On issues like security, and on Ukraine, London and Brussels continue to cooperate. But Brexit remains largely stuck. Economic crises in both the UK and Europe might force the two sides to the negotiating table in earnest. That is the hope, at least, for the start of Truss’s tenure. As Boomgaarden said, Europe has no interest in Britain being another crisis center. “We need Britain,” he said. “And they may need Europe. But they may also need quite a lot of time until they acknowledge [it].”