(Bloomberg) -- Edwin Poots, the newly elected leader of Northern Ireland’s Democratic Unionist Party, called on his supporters to fight against a Brexit deal that has angered unionists and given fresh impetus to calls for a united Ireland.

Poots’s victory over rival Jeffrey Donaldson by 19 votes to 17 comes ahead of an expected summer of heightened tension in Northern Ireland. The region saw the worst violence in years in April, in part fueled by unionist discontent around the Brexit agreement’s so-called Northern Irish protocol. Poots will also have to contend with growing calls for a vote on whether the region should leave the U.K. and join the Irish Republic to the south.

“The Northern Ireland protocol has proven to be a massive challenge for us,” Poots said. “If we are to fight this, to ensure that everybody in Northern Ireland is not worse off as a consequence of the protocol, then it’s for us to do that together.”

The protocol effectively keeps Northern Ireland in the EU’s customs area and much of the single market. That means goods coming from mainland Britain need to be checked before or on entry to the region to ensure they meet the bloc’s rules and standards. Unionists see it as weakening ties to the U.K. while making business more difficult.

More than 70 police were injured in rioting last month which was at least partly fueled by Brexit, and tensions remain. More protests are expected over the summer, especially if the protocol remains in its current form.

“To say unionism is in crisis is perfectly right,” Adrian Guelke, emeritus professor of politics at Queen’s University Belfast, said. “Given the mood of the general unionist and loyalist public about the protocol it’s going to be a very rough ride indeed.”

Poots, 55, has long been known as a hard line opponent of the protocol, even though as agriculture minister he’s responsible for enforcing checks at Northern Ireland’s ports. During the leadership campaign he made clear he doesn’t plan to become first minister in Northern Ireland’s devolved assembly, unlike his predecessor Arlene Foster. Another DUP lawmaker, Paul Givan, may be tapped for that role, according to the Belfast Telegraph, while Poots will be party leader.

Poots is steeped in the DUP. His father was a founding member of the party under Ian Paisley in 1971, while he himself joined in 1981. Poots has been a lawmaker for the party in the assembly since 1998.

Poots’ socially conservative views have also drawn attention: he once told the BBC he believed the earth was about 6,000 years old and attempted to challenge a court ruling allowing gay and unmarried couples to adopt children, according to the broadcaster. Last year he said nationalist areas of Northern Ireland had about six times more coronavirus transmission than unionist areas.

The protocol is the immediate issue he will have to deal with, though the prospect of a united Ireland is perhaps the key long term matter. Largely unthinkable a decade ago, Brexit and changing demographics in the region have moved the topic toward the top of the agenda.

Northern Ireland’s 2021 census, due to be released in 2022, may show Catholics outnumbering Protestants for the first time, with religious identity tending to be a good indicator of attitude toward a united Ireland. A generation has also passed since the 1998 Good Friday agreement, which largely ended three decades of violence in the region.

An Irish Independent survey earlier this month showed a slim lead for those wishing to remain in the U.K. — 44% to 35% — with 17% undecided. Still, the survey found that a majority want a referendum within five years. In a similar poll in 2019, there was just 38% support.

“I will encourage all unionists to work with me to deliver an end, which ensures we set the foundations in this 2021 for another 100 years of Northern Ireland within the United Kingdom,” Poots said in his acceptance speech.

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