Historically, the United States of America saw itself as a blossoming continental nation-state. Accordingly, the first governing body for the North American colonists was called the Continental Congress, which sought to receive delegates from across the populated continent, including the future Canadian provinces of Quebec and Nova Scotia.
Continentalism later became largely associated with the ideology of Manifest Destiny, which included Spanish territories (now Latin America), western U.S. as well as Canada. Due to this, this continentalism grew so much in the United States of America that it transformed into nationalism. Most of the inhabitants of this country, if not all, call themselves "Americans" as if it was a demonym, and say America to refer to the country United States of America instead of the continent America. For a more extensive discussion over this polemical case, read the main article: Use of the word American.
In Canadian political history, continentalism has referred to policies that emphasize Canadian trade and economic ties within the North American continent, particularly the United States, over those with the United Kingdom and the British Empire. In the 19th century Continentialism was one of the three main theories of Canadian nationality, the others being pro-British Imperialism, and Canadian independence.
The most extreme form of Continentalism is Annexationism, which advocates all or part of Canada joining the United States. "Annexationism" has always been a very small minority position in Canada, opponents of continentalism often argue that stronger ties with the United States could eventually lead to annexation, and that this is to be feared. Continentalists themselves may or may not be in favour of continuing to deepen ties with the United States beyond the economic and into areas like a customs union, common border, common currency, or even political union.
However, the Progressive Conservative Party took on many continentalist policies beginning during the Brian Mulroney government in the 1980s, which promoted and successfully signed the North American Free Trade Agreement. These policies were maintained by the Liberal and Conservative Party of Canada governments that followed Mulroney's.
Continentalism today is seen in both negative and positive terms. Canadian economic nationalists typically oppose continentalism. Opposing this, many pro-market neo-liberals and neo-conservatives tend to favour it, on the grounds that it opens up commercial and economic opportunities, allowing free trade between nations.