Mark Carney to lose star environmentalist from caucus

By Mickey Djuric, Zi-Ann Lum | 05/28/2026 06:06 AM EDT

Steven Guilbeault will exit the Liberal caucus as the prime minister breaks with former Prime Minister Justin Trudeau on climate policy.

Steven Guilbeault speaks at a podium.

Steven Guilbeault speaks during the fourth session of the U.N. Intergovernmental Negotiating Committee on Plastic Pollution in Ottawa on April 23, 2024. Dave Chan/AFP via Getty Images

OTTAWA — Mark Carney’s oil-and-gas-friendly policies are about to cost him a star lawmaker, dealing a fresh blow to the prime minister’s fragile majority government and environmental credibility.

POLITICO has confirmed that Steven Guilbeault will announce his resignation Wednesday, according to a person granted anonymity to discuss the decision before it is made public.

He’ll later address the House of Commons about the move, amid disillusionment with the trajectory of Carney’s Liberal government policies.

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Guilbeault declined to comment.

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