First terms in the House of Commons (1984–1993)

Nicholson was first elected to federal parliament in the federal election of 1984 as a Progressive Conservative, defeating New Democrat Richard Harrington and incumbent Liberal Al MacBain. He was re-elected by a narrower margin in the 1988 election, defeating Liberal Gary Pillitteri by fewer than 2,000 votes.

During the 33rd Canadian Parliament, he served on the standing committees responsible for justice (vice-chairman), foreign affairs, national defence and transport. Nicholson also served on the special committee on child care.^[2]

During the 34th Canadian Parliament, he continued to serve on the justice committee and was also named a parliamentary secretary, supporting the Government House Leader (1989-1990) and the Attorney General of Canada (1989-1993) in Prime Minister of Canada Brian Mulroney's government.

Following Kim Campbell's appointment as prime minister, Nicholson joined the cabinet as Minister for Science and Minister responsible for Small Business.^[3]

As with all of his caucus colleagues, save for Jean Charest and Elsie Wayne, he was defeated in the 1993 election, finishing third behind Pillitteri and Mel Grunstein of the Reform Party.

Municipal politics

Nicholson was elected as a trustee for the Niagara Catholic District School Board in 1994. He was elected to the Niagara Regional Council later in 1997, and was re-elected in 2000, and 2003.^[2] He ran for Chairman of the Regional Municipality of Niagara in late 2003, but lost to St. Catharines Regional Councillor Peter Partington.

He attempted to regain his old Commons seat in the 1997 election, but again finished third. He did not seek election to the Commons in the 2000 election.

Return to Opposition in 38th Parliament

The Progressive Conservatives merged with the Canadian Alliance as the Conservative Party of Canada in early 2004, and Nicholson joined the new party. He was narrowly returned to parliament in the 2004 election, defeating Liberal Victor Pietrangelo by more than 1,000 votes.

Nicholson served as Shadow Transportation Critic from July 2004 to January 2005. He was appointed Chief Opposition Whip on January 28, 2005.^[2]

During the 38th Canadian Parliament, he was one of only two members of the 99-member Conservative caucus in the Commons who had previously served in the federal cabinet.

Harper government (2005-2015)

Nicholson was re-elected in the 2006 election and appointed to the Harper cabinet as Government House Leader.^[1]

Back in opposition (2015-2019)

This article needs to be updated. (September 2019)

While the Conservatives were relegated to the Official Opposition after the 2015 election, Nicholson was re-elected and announced his intention to run for the interim leadership of the party. He was defeated by Rona Ambrose, and was subsequently named as the Conservative Justice Critic.^[9]

Nicholson did not run for re-election in the 2019 federal election.^[10]