A timeline of a cabinet resignation: Inside Guilbeault’s decision to resign

MP Steven Guilbeault resigned from Prime Minister Mark Carney's cabinet on Thursday due to his strong opposition to Ottawa's approval of an Alberta pipeline.

OTTAWA — Quebec Liberal MP Steven Guilbeault resigned from cabinet on Thursday, after spending all six years he has been a member of Parliament around that table.

The final decision was made in the last few days but it was a choice that was months in the making.

The Canadian Press spoke to a source with knowledge of the week’s events, who spoke on background about the days leading up to the decision.

Here’s a timeline of how it unfolded.

Before Monday, Nov. 23:

Guilbeault came into politics after a decades-long career as an environmentalist and activist, including as the founder of Quebec’s Equiterre organization. He left that organization in 2018, and a few months later won the nomination to run for the Liberals in a Montreal riding, under then-prime minister Justin Trudeau. He won the riding for the Liberals in September 2019.

Guilbeault was initially the heritage minister but was moved to the environment file after the 2021 election. Under his leadership there, the federal government moved on multiple regulations and climate policies. Those included legislation to enshrine Canada’s emissions goals, and regulations including the oil and gas emissions cap, electric vehicle sales mandates, methane reductions from oil production and clean electricity regulations to get Canada’s grid to net-zero, initially by 2035, a date that was later pushed to 2050.

Guilbeault endorsed Carney for the Liberal leadership on Jan. 21, saying Carney had led through economic crises in Canada and the U.K.

“I know he’s the right person to help bring us into the next phase of our work to support Canadians, to build a strong economy and to fight climate change,” he said at the time.

About a month later, that commitment was tested, as Carney said he would eliminate consumer carbon pricing, a policy Guilbeault had taken political heat to defend over previous years. Despite that, Guilbeault’s endorsement remained intact.

When Carney became prime minister, he kept Guilbeault in cabinet, even as he moved aside several other more left-leaning MPs who had been in Trudeau’s cabinet. However, he did move Guilbeault out of the environment portfolio and returned him to heritage, under the new name minister of Canadian culture and identity. He left Guilbeault with the responsibility for Parks Canada, and also made him his Quebec lieutenant.

Serious reservations about Carney’s climate commitment began to bubble this fall, as his government refused to talk about emissions targets, and talk of backing a new oil pipeline as a major project began to go public.

Discussion of a new pipeline became more pronounced as Carney began referring projects to the Major Projects Office this fall, and negotiations with Alberta on a new climate and energy pact proceeded.

Guilbeault had made Carney and his staff aware as early as the spring that federal backing for a pipeline would make it very hard for Guilbeault to remain in cabinet. But he, like many other Liberals, was watching to see what would happen.

Guilbeault, no longer in the environment seat at the cabinet table, was not part of those negotiations.

Monday, Nov. 23:

CBC broke news of the details of a new memorandum of understanding Carney and Alberta Premier Danielle Smith were set to sign on Nov. 27.

It was the first time Guilbeault and other Liberals got to see what was really on the table, and the scale of the pullback from environmental policies, including the clean electricity regulations — without an equivalent and substantial increase in industrial pricing — and opening the door to exempting a new pipeline from the oil tanker ban of B.C.’s coast.

Tuesday, Nov. 25:

Guilbeault sought a briefing from Carney’s office on the measures in the MOU and received one. Among those at the briefing were Marc-André Blanchard and Christiane Fox, the deputy clerk and associate secretary to cabinet.

The briefing took place prior to the cabinet meeting, which was scheduled to begin at 3:30 p.m., much later than the cabinet meeting’s normal start time of 10 a.m. Reporters began to hear rumblings of Guilbeault’s concerns about the MOU. He arrived for the cabinet meeting stone-faced, and brushed past reporters without a word.

A few minutes later he walked out, again saying nothing, and met briefly with Housing Minister Gregor Robertson in an office down the hall. Eventually Guilbeault returned to the cabinet meeting.

Following its conclusion, reporters saw him in the hallway behind the cabinet area doors, appearing unhappy.

Guilbeault met with Carney for an hour following that meeting. He did not resign but expressed his concerns with the MOU.

Wednesday, Nov. 26:

Guilbeault received a written copy of the MOU. It included not only the pulling back of multiple regulations to cut emissions, but it also included language extending eligibility for federal investment tax credits to enhanced oil recovery projects.

Originally the federal tax credits excluded enhanced oil recovery, a carbon-storage technology that captures carbon dioxide from industrial emitters, and injects it back underground at oilfields. That increases pressure and pushes more oil out of the rock. That carbon dioxide is trapped underground, but it allows for increased production from oilfields.

Adding enhanced oil recovery to tax credits is considered by environmental leaders, including Guilbeault, to be a direct subsidy for oil production, and it was purposely excluded from the original tax credits for that reason.

Guilbeault and Green Party Leader Elizabeth May had both heard rumours before the federal budget was tabled that it was going to amend the tax credits to include enhanced oil recovery.

It was one of the things keeping May from supporting the budget.

Guilbeault got some assurances that would not be in the budget, or added to it after, and was dispatched by the PMO to convince May to vote with the Liberals. She voted with the government on the budget on Nov. 17, the only non-Liberal MP to do so.

Guilbeault wrote to Carney on Wednesday night, informing him that with the MOU as it stood, he could not stay in cabinet.

Thursday, Nov. 27:

Guilbeault spoke to both Carney and Blanchard in Calgary. He formally resigned his cabinet seat.

“Despite this difficult economic context, I remain one of those for whom environmental issues must remain front and centre,” he said in a post outlining why he resigned.

“That is why I strongly oppose the memorandum of understanding between the federal government and government of Alberta.”

This report by The Canadian Press was first published Nov. 28, 2025.

Mia Rabson, The Canadian Press