Career
Between 1916 and 1918, Burnham served overseas as a captain of the 93rd Battalion of the Canadian Expeditionary Force. He was also the author of Canadians in the Imperial Naval and Military Service Abroad. He was re-elected in the 1917 election as a Unionist.
Several months later he resigned his seat in the House of Commons and ran for re-election as an Independent Conservative in a February 7, 1921 by-election in hopes of demonstrating that public opinion supported him.
Burham argued that the Meighen government "is the creature of some big schemes now floating in the air and I believe it is a positive danger to Canada. I am unalterably opposed to this combination at Ottawa and will never rest until I see those who are attempting to wreck the old parties, whose backing and policies are known and understood, are themselves wrecked."
He lost the by-election and ran again as a straight Conservative in the 1921 general election in December but was again defeated.
With the defeat of the Meighen government, Burnham called upon the party to hold a national leadership convention, abandon the "National Liberal and Conservative Party" concept and return to its old Conservative form.