John Horne Blackmore

John Horne Blackmore (March 27, 1890 – May 2, 1971), a school teacher and principal by training, was the first leader of what became the Social Credit Party of Canada, a political party in Canada that promoted the social credit theories of monetary reform.

Blackmore was first elected to the Canadian House of Commons in the 1935 election as Member of Parliament representing Lethbridge, Alberta for the fledgling Social Credit movement which had swept to power in Alberta in the 1935 Alberta provincial election weeks earlier. He was chosen the party's parliamentary leader. In 1939 Social Credit merged into William Herridge's New Democracy movement with Herridge acknowledged as the new party's leader. However, Herridge failed to win a seat in the 1940 federal election and in the subsequent parliament Blackmore led the New Democracy MPs, all former Social Crediters, who had been elected.

Blackmore remained party leader until 1944 when Social Credit held its first national convention and acclaimed Solon Earl Low as leader. He remained an MP until he was defeated in the 1958 election in which Social Credit lost all of its MPs.

Blackmore was the first Mormon to be elected to the Canadian House of Commons and was excommunicated by The Church of Jesus Christ of Latter-day Saints in 1947 for "teaching and advocating the doctrine of plural marriage" at secret meetings in southern Alberta. At such meetings, men debated whether Mormon leaders were wrong to have renounced Joseph Smith's revelation regarding polygamy. Though not a polygamist himself, Blackmore urged Parliament to repeal the anti-polygamy law and succeeded in removing specific references to Mormons in the law. His nephew, Winston Blackmore, is the leader of Canada's largest polygamist group and was charged by the RCMP with polygamy in 2009. He is currently challenging the law's constitutionality.

John Horne Blackmore was criticized for his views on Jews and it was said he "frequently gave public aid and comfort to anti-Semitism" along with his successor as national Social Credit leader, Solon Low. In 1953, it was reported that Blackmore was distributing the anti-Semitic Protocols of the Elders of Zion from his parliamentary office.