Dinsdale was a
Progressive Conservative Member of Parliament (MP) from 1951 until his death in 1982, being first elected in a 1951
by-election with an upset victory to take a seat previously held by the
Liberals. Dinsdale was originally hesitant about running in the by-election, and was fired by Brandon College soon after his nomination. Dinsdale won 56.9% of the vote in that by-election. During his tenure in the
House of Commons of Canada, he represented the
riding of
Brandon for one year in 1951 until it was merged with the neighbouring riding of
Souris to form
Brandon—Souris. He held Brandon-Souris from 1952 until his death in 1982, winning 11 consecutive election victories. At the time of his death he was the
Dean of the House - the longest-serving
Member of Parliament. During his period as MP, he was the
parliamentary assistant to the
Minister of Veterans Affairs in 1957, and
parliamentary secretary to the same minister in 1960. He then joined the
Cabinet of
John Diefenbaker as
Minister of Northern Affairs and National Resources from 1960 to 1963. He was also acting
Minister of Mines and Technical Surveys for a few months in 1961. In 1963, while serving as
Minister of Northern Affairs and National Resources he chaired the "Resources for Tomorrow" conference, which led to the establishment of a
Department of the Environment. Dinsdale worked tirelessly for many causes, including
First Nations, international human rights, immigrant Canadians and most notably disabled persons. He was vice-chair of the Special Committee on the Disabled, whose work led to many improvements in services for disabled Canadians, and worked with many international governments and organizations to improve the lives of the disabled everywhere, and in 1981 was Canada's delegate to the United Nations for the
International Year of Disabled Persons. ==Honours==