The term Manifest Destiny was first used in 1845 by New York City journalist John Louis O’Sullivan in the context of the annexation of the Republic of Texas to the American Union as the 28th state. Manifest Destiny came to represent a larger ideology characterized by the mission of American expansionism across the North American continent. This took place amid calls by politicians and citizens in the United States to claim geographical control over land remaining under British possession, namely the Province of Canada (formally Upper Canada and Lower Canada), New Brunswick and Nova Scotia.
In the aftermath of the American Revolution (1775–83), people living in the United States were distrustful of the continued British presence in North America. After the War of 1812 (1812–14), people debated the fate of the remaining colonies in British North America. Since they were not collectively unified as a nation, these were vulnerable to American aggression and interference. It was assumed by advocates of Manifest Destiny that British colonies could be easily assimilated into an American system of governance and economics.
Fearing invaders from the south, Canadian expansionism was considered by some as a pre-emptive action to reduce the chances that territories to the west and north of the Canadas would be annexed by the United States. While the British adopted an official policy of neutrality during the American Civil War (1861–65), newspapers published in the northern Union states suggested that territory lost in the American South could be balanced by northward expansion into Canada. North Americans reacted in diverse ways to the concept of Manifest Destiny. Some welcomed promises of American “emancipation” of British North America, while those faithful to the British maintained a tradition of Loyalist support of the Crown similar to that during the American Revolution.
The economic threat of American invasion diminished somewhat after Confederation in 1867, and under the leadership of the federal Conservative Party and Sir John A. Macdonald, who implemented the National Policy in 1879 to favour Canadian manufacturers from the threat of American competition. The National Policy would contribute to Canadian efforts to push west and north, amid the growth of the Canadian Pacific Railway and immigration policies that favoured the settlement of the West by government-approved settlers under the Dominion Lands Act of 1872.
Manifest Destiny contributed to a growing sense of national identity, which culminated in the Charlottetown Conference of 1864, and political efforts to unify British colonies in North America. As the British Empire began to move toward a policy of free trade, the expense of defending and administering colonial governments in North America became more and more untenable for the ageing empire. The emergence of responsible government in the Canadas, the repeal of the Corn Laws in 1846 and the defeat of the Confederate Army in the United States in 1865 complemented British desires to take a lesser role in the governance of the Canadian provinces as they moved in the direction of Confederation in 1867. Alongside these developments, Manifest Destiny occupied an important place in the symbolic imagery of conquest and colonialism in 19th century North America. Consequently, it factored into efforts to push west and north, settling the Prairie Provinces and the Arctic, indicating the persistence of an expansionist urge on behalf of the Canadian state.
Manifest Destiny speaks to the shared pasts of Canada and the United States as governments that formed after the British colonization of North America. It has come to represent a persistent theme in efforts to map the similarities and differences between Canadians and Americans. In both national examples, the push westward took the most drastic toll on Indigenous peoples of areas affected by these mutual expansionist tendencies, who experienced forced dislocation and long ranging negative effects of the imposition of foreign models of governance over their political sovereignty.