Scotland’s leader resigns. His government couldn’t agree on climate change, health care.

Scotland’s first minister, Humza Yousaf, resigned on April 29, triggering a leadership contest as the governing Scottish National Party seeks to avoid early elections.

Mr. Yousaf, whose party has been weakened by a campaign finance scandal and divisions over transgender rights, was finally brought down by his decision to oust the Green Party from his governing coalition because of differences over climate change goals. He was forced to resign after that left him unable to cobble together a majority in Scotland’s devolved regional parliament.

With no prospect of victory in two confidence votes later this week, Mr. Yousaf quit rather than face defeat.

“I’ve concluded that repairing our relationship across the political divide can only be done with someone else at the helm,’’ he told reporters in Edinburgh, Scotland’s capital. “I have therefore informed the SNP’s national secretary of my intention to stand down as party leader.”

Mr. Yousaf will remain first minister as the SNP tries to choose a replacement who can command a majority in the Scottish parliament. If it fails to do so, Scotland faces the possibility of early elections.

The debacle in Scotland adds to the fevered political climate in the broader United Kingdom, where concerns about immigration, health care, and government spending have undermined support for the governing Conservative Party.

The Conservatives and the opposition Labour Party had proposed separate no-confidence motions as they sought to weaken the SNP before a U.K.-wide parliamentary election expected to take place later this year. The SNP has been the dominant party in Scottish politics for almost two decades and currently holds 43 of the country’s 59 seats in the U.K. Parliament.

On May 2, England and Wales will hold local elections that are seen as barometer of support for Prime Minister Rishi Sunak’s government.

With all of the other parties in Scotland’s parliament lined up against him, the tight electoral arithmetic meant that Mr. Yousaf’s fate hinged on the upstart Alba Party, which holds just one seat. The SNP has 63 of the 128 voting lawmakers, leaving Mr. Yousaf one vote short of what he needed to eke out a victory.

But striking a deal with Alba was always going to be politically fraught.

Founded in 2021 by former SNP leader and first minister Alex Salmond, Alba sees itself as the true voice of Scottish independence. As the price of its support, Alba demanded that Mr. Yousaf put independence at the top of his agenda, move away from divisive “identity politics” and focus on issues such as jobs, education, and investment in Scottish industry.

It was a step too far for Mr. Yousaf.

“While a route through this week’s motion of no confidence was absolutely possible, I am not willing to trade my values and principles or do deals with whomever simply for retaining power,” he said.

Alba’s central role in the crisis is symbolic of the disarray confronting Scotland’s independence movement a decade after voters rejected the SNP’s plan to sever ties with the U.K.

Mr. Yousaf became the leader of the SNP and first minister of Scotland in March 2023 after former leader Nicola Sturgeon stepped down, citing the toll more than eight years in office had taken on her.

Ms. Sturgeon’s resignation came during a police investigation into allegations that the party had misused money donated to fund a second independence referendum.

Ms. Sturgeon was questioned and released without charge last June. Her husband, former SNP treasurer Peter Murrell, was charged with embezzlement earlier this month. Both deny any wrongdoing in the case.

Support for the SNP also declined after the party backed legislation to make it easier for people to change their gender and implemented a hate crime law that made transgender identity a protected characteristic, even though the same protections weren’t given to all women.

Then came Mr. Yousaf’s decision to scrap Scotland’s goal of reducing carbon emissions by 75% by 2030.

Although he said Scotland would still achieve its goal of net-zero carbon emissions by 2045, the decision sparked tensions with his coalition partners. The Green Party initially backed the change, but party leaders said they would poll the broader membership and reverse course if necessary.

Last week, Mr. Yousaf abruptly ended a power-sharing agreement with the Greens, embarrassing the party’s two government ministers who had arrived for a Cabinet meeting.

“I clearly underestimated the level of hurt and upset that caused Green colleagues,’’ Mr. Yousaf said. “For a minority government to be able to govern effectively and efficiently, trust when working with the opposition is clearly fundamental.’’

Labour is the biggest beneficiary of the ructions within the SNP because both parties support left-leaning policies on issues such as worker rights and government spending. That has huge implications for this year’s general election as Labour tries to wrest control of the U.K. Parliament from the Conservatives.

The Labour vote in Scotland dropped to 18.6% in the 2019 general election from 45.6% in 1997. During the same period, support for the SNP jumped to 45% from 22.1%. Labour currently has just one member of Parliament from Scotland.

This story was reported by The Associated Press.