As the child of American
refugees and having lived six years in the
United States, De Cosmos developed a sharpened sense of
nationalism. This was expressed in a growing
protectionist economic sentiment, and the belief that the colonies of British North America needed to be self-supporting, develop a distinct identity, and form a political and economic union. From such policies, emerged the two great causes of his later career: the
union of Vancouver Island and British Columbia, and the merged Colony of British Columbia's entry into the
Canadian Confederation. To advance the first cause, De Cosmos left journalism and entered politics, becoming a member of the
Legislative Assembly of Vancouver Island from 1863 until its union with the Colony of British Columbia in 1866. He advanced the second cause through his position as a member of the assembly of the
merged, larger British Columbia from 1867 to 1868 and 1870 to 1871, and as the leading force (with
Robert Beaven and
John Robson) behind the colony's Confederation League. Through the instrumental role De Cosmos played in realizing these two goals, he earned for himself his reputation as British Columbia's
Father of Confederation. At the time of British Columbia's entry into Confederation on July 20, 1871, De Cosmos was the leading pro-Confederation figure in the new
province. That year, he was elected to represent Victoria in both the
provincial legislature and the
House of Commons. Despite his prominence — or perhaps because of it —
Lieutenant Governor Sir Joseph Trutch passed over De Cosmos for the job of
Premier, instead asking
John Foster McCreight to assume the position.
Premier of British Columbia McCreight resigned in 1872 on a
motion of non-confidence, and on December 23, 1872, Trutch asked De Cosmos to form a new government as Premier. De Cosmos populated his cabinet with reformers, mostly born in North America, many of whom would come to dominate provincial politics for the generation. His government pursued an agenda of political reform, economic expansion, and the development of public institutions—especially schools. De Cosmos was a member of a group of entrepreneurs that saw an opportunity for a steel industry in B.C. using the newly discovered iron deposits on Texada Island, coal from Vancouver Island with a smelter and rolling mill in Vancouver. Rails for the transcontinental railway proposed western construction starting in Vancouver to meet the push from the east would provide the immediate market for the product. Involving himself in this venture in his position as Premier was considered a
conflict of interest and precipitated the Texada Scandal and the second B.C. Royal Commission of Inquiry. He resigned as Premier. The Commission however found him not guilty.
Member of Parliament Despite having resigned as Premier, De Cosmos continued to be re-elected as a
Liberal Member of Parliament for
Victoria City. Consistent with federal promises to place the terminus of the transcontinental railway in Victoria, De Cosmos, in
Ottawa, pushed for completion, especially of the Vancouver Island
portion. De Cosmos also became an opponent of land concessions to
First Nations in the province, seeing it as a hindrance to British Columbia's economic growth and settlement by those of European descent. It is generally conceded that De Cosmos's tenure as a member of the dominion parliament was undistinguished . ==Retirement and death==