Lamoureux first ran for the
Legislative Assembly of Manitoba in the
1986 election in the north-
Winnipeg division of
Logan. The Liberal Party did not have a strong provincial organization in this campaign, and Lamoureux finished a distant third against
New Democrat Maureen Hemphill. The Manitoba Liberal Party saw its popularity increase between 1986 and 1988, as many centre-left voters abandoned the New Democratic Party (NDP) government of
Howard Pawley. In the
1988 election, the Liberals jumped from one seat—
River Heights, represented by party leader
Sharon Carstairs—to twenty and became the dominant party in both north and south Winnipeg. Lamoureux scored a narrow victory over NDP incumbent
Don Scott in the north end division of
Inkster and entered the legislature as a member of the
Official Opposition. The Liberal Party fell back to seven seats in the
1990 provincial election, finishing in third place behind a resurgent New Democratic Party. Lamoureux, however, was re-elected in Inkster with an increased margin of victory. ;Leadership campaigns Lamoureux ran for the Manitoba Liberal Party's leadership in 1993 after the resignation of Sharon Carstairs. He was seen as an "anti-establishment" candidate in this contest, representing north-Winnipeg communities against a party establishment dominated by south-Winnipeg interests. He lost to
Paul Edwards. The Liberals were leading in the polls before the
1995 provincial election, but their support base collapsed during the campaign and the party won only three seats. Lamoureux again increased his majority in Inkster, while Edwards lost in
St. James. Edwards announced his resignation in late 1995, and Lamoureux again stood for the party leadership. He was again regarded as an "anti-establishment" candidate, this time facing
Ginny Hasselfield, who was supported by the party's leadership. This contest was very divisive, and its ending was controversial. All party members could cast a ballot, and the results were "weighted" by constituency. It is generally acknowledged that Lamoureux received more votes from the party members than Hasselfield. Because his support was concentrated in north Winnipeg, however, Hasselfield won the weighted vote by 21 points. ;Defeat and return The divisions in the Manitoba Liberal Party continued after the leadership contest. Following the
1997 Canadian federal election, Lamoureux and
Gary Kowalski announced that they could no longer support Hasselfield's leadership and would sit as "Independent Liberals". This decision left
Neil Gaudry as the party's only official member of the legislature. Facing increased pressure, Hasselfield agreed to resign as party leader in early 1998. Former MP
Jon Gerrard was elected as her successor, and Lamoureux and Kowalski rejoined the party caucus. The Liberal Party entered the
1999 provincial election in a weakened state, damaged by the divisions of the previous years. The election itself became polarized between the governing
Progressive Conservatives and the opposition New Democratic Party, and the Liberal Party's support fell significantly. Although still personally popular, Lamoureux was narrowly defeated by New Democrat
Becky Barrett. Lamoureux ran as a
Liberal Party candidate in
Winnipeg Centre in the
2000 Canadian federal election. He finished second to
New Democratic Party (NDP) incumbent
Pat Martin. Becky Barrett did not seek re-election in 2003, and Lamoureux was again elected to the legislature for Inkster. The only other Liberal to win election in this campaign was Jon Gerrard. Both Lamoureux and Gerrard were re-elected in the
2007 election, but the party did not make any further gains. ==Member of the Canadian House of Commons==