~12 Progressive MPs join Liberals or UFA

The Progressive Party of Canada, which had won 65 seats in the 1921 election to become the second-largest party in Parliament, gradually disintegrated during the 1920s as Mackenzie King's Liberals skillfully co-opted Progressive policies and wooed individual Progressive MPs. By the 1925-1926 Constitutional Crisis and King-Byng Affair, the Progressive caucus had splintered into three factions: the "Ginger Group" of principled agrarian radicals (Robert Gardiner, J.S. Woodsworth, Agnes Macphail, William Irvine), who would eventually form the CCF; the moderates led by Robert Forke, who drifted toward the Liberals; and the United Farmers of Alberta MPs who maintained their separate identity. Approximately 12 Progressive MPs crossed to the Liberals between 1924 and 1926, including John Frederick Johnston (who physically crossed the floor in a dramatic gesture) and Robert Forke himself, who was appointed to Mackenzie King's cabinet as Minister of Immigration.

The Progressive Party effectively ceased to exist as a parliamentary force after 1930. Its disintegration followed two paths: the moderate, pro-Liberal wing was absorbed into King's coalition, while the radical agrarian wing evolved into the Ginger Group and ultimately helped found the Co-operative Commonwealth Federation (CCF) in 1932 — the forerunner of today's NDP. The 1920s Progressive experience was the blueprint for how Canadian minor parties typically end: co-opted by the Liberals from the centre or radicalized into new formations on the left.