Conservative Housing Critic Scott Aitchison to Resign Ontario Seat
Conservative MP Scott Aitchison will resign his Parry Sound-Muskoka seat by the end of the year, sources told The Globe and Mail.
Aitchison told Conservative Leader Pierre Poilievre of the decision last week. CTV first reported the news, while CBC News reported separately, citing three sources, that he is expected to resign later this fall.
Aitchison is the housing critic in Poilievre's shadow cabinet (the opposition MPs assigned to challenge ministers on specific files) and represents Parry Sound-Muskoka in Ontario. House of Commons records list him as a Conservative member of the 45th Parliament, with his current term starting April 28, 2025. He has held the riding since 2019 and won re-election in 2025 with 52.2 per cent of the vote. He has been in politics since 1994.
Aitchison ran against Poilievre for the Conservative leadership in 2022 and finished fifth. Two sources said he wants to try something else outside elected life. CTV News reported, citing a source close to Aitchison, that the resignation will come by the end of the year.
Sources say the departure will create another vacancy for Poilievre. The Front Bench panel on CTV News called the resignation "a real body blow" for Poilievre.
The losses have continued for months. Conservative MP Larry Brock formally resigned his Brantford-Brant South seat earlier this month after saying this summer he would step down. Saskatchewan MP Cathay Wagantall resigned on Aug. 31 after announcing in June she would leave. Four Conservative MPs have crossed the floor to the Liberals since last November. Quebec MP Richard Martel resigned for a Senate appointment, and the Conservatives lost his riding in the August byelection (a special vote held to fill an empty seat).
The seat count before this vacancy is 173 Liberals, enough for a majority government, and 137 Conservatives including Aitchison, with six vacancies. Cited Nanos Research polling puts Liberal support at 49.9 per cent and Conservative support at 27.9 per cent.
The broader context here is managing a caucus when the other side holds a majority, and it helps explain why one Ontario resignation matters beyond the local byelection. It is like trying to run a full schedule with a short bench. For party managers, the issue is not only the writ (the formal order that starts a byelection) in Parry Sound-Muskoka. It is the pattern of exits and floor crossings that forces a leader to fill critic jobs, defend safe seats, and keep MPs focused on Parliament rather than personnel. A housing critic counts in that calculation because housing is shared jurisdiction, meaning Ottawa sets spending and mortgage rules while provinces and municipalities control supply, approvals and tenancy.
Looking at what this means for Poilievre, the short-term questions are practical. A vacancy leaves a byelection to be called on the government's timeline, a critic post to cover and a riding association to rebuild. The longer question is retention. When departures spread across regions, from southern Ontario to Saskatchewan to Quebec, whips and House leaders (the MPs who organise attendance and committee work) watch attendance, committee assignments and candidate recruitment more closely. That pattern, rather than any single resignation, will shape Conservative positioning heading into the next sitting.
