The Progressive Conservatives were reduced to a fragile minority government in the 1985 election. Mitchell was named as a minister without portfolio and Chief Government Whip on May 17, 1985, but accomplished little in this position before Miller's government was defeated in the house. In opposition, he served as his party's critic for energy.
On June 16, 2007, Mitchell died after a long battle with cancer. He was surrounded by friends and family at the time of his death. Coincidentally, Mitchell received his medical care at the Queensway Carleton Hospital in Ottawa, Ontario, which he had been affiliated with numerous times during his political career.
References
^Stead, Sylvia (November 21, 1980). "Tories keep Carleton in Ontario by-election". The Globe and Mail. p. 1.