Thomas Joseph "Tom" Mulcair (born October 24, 1954) is the Leader of the Official Opposition in Canada, a lawyer, university professor, and politician. A New Democratic Party Member of Parliament for the electoral district of Outremont in Quebec since 2007, he was selected as the leader of the New Democratic Party, thus the Leader of the Official Opposition, in the leadership election on March 24, 2012, with 57.2% of the votes on the fourth and final ballot.

He was the provincial Member of the National Assembly of Quebec for the riding of Chomedey in Laval from 1994 to 2007, holding the seat for the Liberal Party of Quebec. He served as the Minister of Sustainable Development, Environment and Parks from 2003 until 2006, in the Liberal government of Premier Jean Charest. Elected MP for Outremont in a by-election in 2007, he was named Deputy Leader of the New Democratic Party, jointly with Libby Davies, shortly afterwards, and has won re-election twice.

On May 26, 2011, he was named the New Democratic Party's Opposition House Leader. On March 24, 2012, Thomas Mulcair was elected to be the new federal NDP leader, succeeding the late Jack Layton. Prior to entering politics, Mulcair was a senior civil servant in the Quebec provincial government, ran a private law practice, and taught law at the university level.

Stephen Joseph Harper, PC MP (born April 30, 1959) is the 22nd and current Prime Minister of Canada and leader of the Conservative Party. Harper became prime minister when his party formed a minority government after the 2006 federal election. He is the first prime minister from the newly reconstituted Conservative Party, following a merger of the Progressive Conservative and Canadian Alliance parties.

Harper has been the Member of Parliament (MP) for the riding of Calgary Southwest in Alberta since 2002. Earlier, from 1993 to 1997, he was the MP for Calgary West. He was one of the founding members of the Reform Party, but did not seek re-election, and instead joined, and shortly thereafter led, the National Citizens Coalition. In 2002, he succeeded Stockwell Day as leader of the Canadian Alliance (the successor to the Reform Party) and returned to parliament as Leader of the Opposition. In 2003, he reached an agreement with Progressive Conservative leader Peter MacKay for the merger of their two parties to form the Conservative Party of Canada. He was elected as the party's first non-interim leader in March 2004.

Justin Pierre James Trudeau, MP (born December 25, 1971) is a Canadian politician. He has represented the Montreal electoral division of Papineau in the Canadian House of Commons since 2008 as a member of the Liberal Party and currently serves as the party's critic for youth, post-secondary education, and amateur sport.

Trudeau is the eldest son of the late former Canadian prime minister Pierre Trudeau and Margaret Sinclair Trudeau Kemper. His maternal grandfather, James Sinclair, was also a federal cabinet minister.

Trudeau was born on December 25, 1971, in Ottawa, Ontario. He was only the second child in Canadian history to be born when one of his parents was prime minister; the first was John A. Macdonald's youngest daughter Margaret Mary Macdonald, and Trudeau's younger brothers Alexandre (Sacha) (born December 25, 1973) and Michel (1975–98) were the third and fourth, respectively. Pierre and Margaret Trudeau separated in 1977, when Justin was six years old, and Pierre retired as prime minister in 1984. Of his mother and father's marriage, Trudeau said in 2009, "They loved each other incredibly, passionately, completely. But there was 30 years between them and my mom never was an equal partner in what encompassed my father's life, his duty, his country."