The 1920 election proved to be the party's greatest success in Manitoba. In 1921, the SPC lost many of its members to the newly formed Workers Party (which was the legal wing of the Communist Party of Canada) and ceased to function as a viable organization. Armstrong ran again as an SPC candidate in the 1922 election, and was frequently heckled by Workers Party candidates for his alliance with the reformist Independent Labour Party. Armstrong was defeated, and the party formally dissolved in 1925.