The resignation of Arlene Foster could signal a hardening of the DUP's socially conservative policies and greater intransigence around the Northern Ireland Protocol.
Mrs Foster, who is widely viewed as holding more socially liberal views than many in her party, looks set to be replaced by a more conservative candidate.
Agriculture minister Edwin Poots, an Orangeman, remains the front-runner to succeed Mrs Foster.
If he is chosen as DUP leader, relationships with Sinn Féin are likely to come under even more strain, with fears that the Executive could be at risk.
Mr Poots has been a vocal opponent of the Protocol and, as agriculture minister, he has blocked the recruitment of staff to carry out border checks.
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His appointment is expected to see a reshuffle amongst DUP ministers, with education minister Peter Weir, a backer of Mrs Foster, in danger of losing his job.
North Antrim MLA Mervyn Storey, a Free Presbyterian elder who is on the socially conservative wing of the party and is strongly connected to the party's Protestant evangelical grassroots, could be brought back as a minister.
Well-regarded as a politician, Mr Storey, who was close to the late Ian Paisley, is seen as a sure pair of hands who could help to stabilise a fractured party which many members have accused of straying too far from its roots.
Junior minister Gordon Lyons, who stood in for Mr Poots while he had cancer treatment earlier this year, could be permanently promoted as agriculture minister.
A Poots leadership could also see a promotion for Lagan Valley MLA Paul Givan, who had a short tenure as communities minister in 2016/17. A supporter of Creationism, Mr Givan could be brought in to replace Diane Dodds as economy minister.
Under Mr Poots, political flashpoints including contentious loyal order parades are likely to come to the fore again.
Orangemen and loyalist bands are preparing to take part in the annual Twelfth demonstrations in July - a year after parades were cancelled due to the pandemic.
A change of leadership may prompt some loyalists to step up their protests against the Protocol, putting greater political pressure on the British government.
As Northern Ireland prepares to mark its centenary this year, a Poots leadership could see the party moving closer to the views of its founders, including the late Mr Paisley.
A letter from a group of DUP councillors to the party's chairman and chief executive had complained that Mrs Foster and four other MLAs had abstained in a vote on gay conversion therapy this week.
While moves to oust Mrs Foster had been in the works for several months, party members had expressed ongoing concerns about the direction the leadership was taking on social issues.
With continuing disquiet about the relaxation of abortion legislation, campaigners who are fighting for terminations to be more widely available across the north are likely to have a tougher battle on their hands under a Poots leadership.
