Liberal MPs are gearing up for a critical decision on Sunday — whether to grant their caucus the power to initiate leadership reviews under the Reform Act.The consequence would be a leadership review of Prime Minister Mark Carney — a parliamentary practice the Liberals haven’t employed in multiple administrations. The vote, which will be held one day before Parliament resumes, could reshape the party’s internal dynamics and test Carney’s ability to unify a fractious caucus.The Liberal caucus is split nearly evenly between seasoned MPs and newcomers, creating a delicate balancing act for Carney. The Reform Act, which the Liberals declined to adopt in 2021, allows caucus members to trigger a leadership review with just 20% support. The Conservatives, by contrast, embraced the measure post-2021, leading to Erin O’Toole’s ouster and Pierre Poilievre’s rise in 2022..When Justin Trudeau faced mounting internal pressure to resign in the fall of 2024, the Liberals’ lack of a formal mechanism to address leadership challenges was exposed. Trudeau stepped down in January after dismissing Finance Minister Chrystia Freeland, a move that alienated many MPs.Carney’s subsequent leadership win and near-majority victory have bolstered his position, but lingering tensions over his cabinet selections — such as Sean Fraser’s return as justice minister and Gregor Robertson’s appointment to housing — have fueled frustration among some MPs.“There’s a lot of disappointment,” one Liberal MP, speaking anonymously, told iPolitics.“You’ve got veterans who feel sidelined and big-name recruits who expected cabinet roles. Carney’s walking into a tough spot.”The MP noted that while Trudeau’s resignation showed caucus pressure could force change without the Reform Act, the vote’s outcome remains uncertain.“It’ll be interesting to see how Carney navigates this,” they added, pointing to the caucus’s near-even split..Liberal MP Sophie Chatel, a vocal supporter of the Reform Act, argues it would prevent a repeat of last fall’s “chaotic” leadership crisis. She insists Carney should let MPs vote freely, signaling trust in his leadership.“It’s symbolic,” Chatel told the outlet.“The risk of triggering it is low given Carney’s recent win, but it shows confidence in the caucus and avoids messy public disputes.”Chatel also proposes a party rule requiring leaders to seek a renewed mandate after two terms, roughly eight years, citing Trudeau’s nine-year tenure as a cautionary tale.“Voters often want change after that long,” she said, noting exceptions for minority governments.With Parliament resuming on May 26, Carney faces immediate challenges, including managing caucus unrest and preparing for Pierre Poilievre’s anticipated return to the Commons via a by-election in Battle River-Crowfoot. While Carney may enjoy a brief honeymoon period, tougher tests loom in the fall.The Reform Act vote will reveal much about Carney’s grip on the party and whether Liberals are ready to empower their caucus—or rely on informal pressure to keep their leader in check.