41st Parliament

In 2012, NDP Leader Thomas Mulcair appointed Stewart as official opposition critic for science and technology and as a member of the standing committee on industry, science and technology. In Parliament, he opposed the Conservative government's elimination of the long-form census and funding cuts for basic scientific research.^[15] He tabled legislation (Motion 453) to protect scientific integrity in government departments and end the muzzling of federal scientists.^[16]

In 2013, Stewart introduced Bill C-558, The Parliamentary Science Officer Act. Following the elimination of Canada's National Science Advisor in 2008, the bill aimed to create an independent science watchdog tasked with providing Parliament with sound scientific information and ensuring decisions are informed by the best available evidence.^[17] Bill C-558 was endorsed by Evidence for Democracy, the Canadian Association of University Teachers, the Professional Institute of the Public Service of Canada, and the Centre for Science in the Public Interest.^[18]

Stewart put forward a proposal (Motion 428) for the House of Commons to begin accepting petitions electronically as a means to engage more Canadians in the democratic process.^[19] It further proposed that short debates be triggered in Parliament if an online petition receives a significant number of signatures and is sponsored by at least five MPs. Stewart's proposal was endorsed by Ed Broadbent, Preston Manning, and a number of civil society groups.^[20] Being opposed by Prime Minister Stephen Harper and his Conservative cabinet, Motion 428 passed the House of Commons by only two votes (142-140) on January 29, 2014.^[21] It was widely viewed as a "surprise win" for the official opposition.^[22]

Stewart held public consultations with Burnaby residents on Kinder Morgan's proposal to build a new export-only, bitumen-based crude oil pipeline through his riding.^[23] Stewart became a vocal opponent of the project, citing community concerns over property expropriation, decreasing housing values, increased tanker traffic in the Burrard Inlet, the use of temporary foreign workers, and the lack of benefits for British Columbia.^[24] His constituency office helped local residents sign-up to participate in the National Energy Board's review of the project.^[25] In 2013, the Burnaby Newsleader named Stewart their "Newsmaker of the Year" for his community work on the Kinder Morgan pipeline.^[24]

Stewart is an advocate for social housing and federal action to address BC's housing crisis.^[26] In 2014, he put forward a BC-specific affordable housing strategy (Motion 547) to recognize housing as a fundamental right, expand public investments in housing co-ops, maintain rent subsidies for low-income families, set targets for reducing and ending homelessness, and study the impact of investor speculation and housing vacancies on real estate prices.^[27] His motion was endorsed by the City of Burnaby.^[28]

42nd Parliament

He was re-elected in the new riding of Burnaby South in the 2015 election.

Following the election, Stewart was re-appointed by Tom Mulcair as NDP critic for science.^[29]

On December 4, 2015, Parliament launched its new website for accepting electronic petitions from Canadians.^[30] Under the new system, initiated by Stewart's motion that passed before the election, the federal government has to respond within 45 days to online petitions if they are sponsored by one member of Parliament and receive at least 500 signatures.^[31] Stewart sponsored the first official e-petition in Canada on behalf of two local constituents.^[32]

On December 9, 2015, Stewart was elected by his caucus colleagues as chair of the NDP's British Columbia caucus.^[33] In a statement, he vowed to support the NDP's newly elected MPs getting established in Parliament, strengthen engagement with stakeholders and constituents across the province, and hold the new Liberal government accountable for its election promises on affordable housing and pipeline reviews.^[33]

2018 contempt of court

On March 23, 2018, Stewart was arrested for civil contempt during a demonstration against the Kinder Morgan pipeline. Other members of the demonstration, including fellow member of Parliament Elizabeth May, were also arrested concerning the same incident. They were accused of violating a court order requiring those demonstrating to stay five metres back from company work sites, when they allegedly blocked the roadway.^[34] On April 9, 2018, Justice Kenneth Affleck of the British Columbia Supreme Court recommended that Stewart and the others arrested should be charged with criminal contempt in relation to the alleged incident.^[35][36][37] On April 16, 2018, it was reported that special prosecutors would be overseeing the charges against Stewart and May.^[38] On May 14, 2018, Stewart pleaded guilty to criminal contempt of court for his actions during the protest and was fined $500. As criminal contempt is a common law—not a Criminal Code—offence, Stewart does not have a criminal record.^[39][40]

Mayoral term

Post-mayoral activities

After the 2022 municipal election, Stewart was appointed as director of Simon Fraser University's Centre for Public Policy Research.^[13]

In May 2023, Stewart commented on his successor's administration, calling Sim's clearing of the Hastings Street encampment "callous". Stewart also hinted that he would be initiating a legal challenge of Vancouver's at-large electoral system, in which councillors are elected to represent the whole city.^[56]