In the 1935 provincial election, Lymburn and all other United Farmers of Alberta candidates were defeated, as William Aberhart led the Social Credit League to victory.

[5] Once the Great Depression began to breed labour militancy, at Brownlee's request he prepared a list of known Communist leaders so that the government could take action to deport them.

[9] Taking the stand during the trial, Lymburn stated that the investigation had been initiated not to aid in the premier's defence, but because the alleged solicitation was a criminal offence.

[10] When the scandal forced Brownlee's resignation as premier, Lymburn stayed on as attorney-general in the short-lived government of Richard Gavin Reid.

The conservative Reid government was suffering damage to its popularity as a result of the Great Depression, and radical economic theories, most notably the version of social credit espoused by Calgary evangelist William Aberhart, were gaining currency among the public.

As historian Franklin Foster has noted, "it was an ironic footnote to the demise of the most politically successful farmers' group in history that the one UFA candidate who came closest to re-election was lawyer John Lymburn in the City of Edmonton.

"[12] After defeat, Lymburn remained active in community life as an elder in Edmonton's First Presbyterian Church, chairman of the Advisory Board of the Students' Christian Movement, chairman of the board of directors of the Beulah Home for unmarried mothers, and president of the Edmonton Scottish Society.

[14] In 1942, Lymburn contested a by-election in Edmonton; he finished third of five candidates as Elmer Roper of the Cooperative Commonwealth Federation emerged victorious.