From the independence of the United States until today, various movements within Canada have campaigned in favour of U.S. annexation of parts or all of Canada. Historical studies have focused on numerous small-scale movements which are helpful in comparisons of Canadian and American politics. In the early years of the United States, many American political figures were in favour of invading and annexing Canada, and even pre-approved Canada's admission to the U.S. in the Articles of Confederation in 1777. The defeat of American attempts to achieve this goal, both in the American Revolutionary War and the War of 1812, gradually led to the abandonment in the U.S. of any serious push toward annexation. As historian Joseph Levitt notes: Surveys have suggested that a very small minority of Canadians would potentially support annexation, ranging from as many as 20 percent in a survey by Léger Marketing in 2001 to as few as seven percent in another survey by the same company in 2004. No elected member of any federal or provincial assembly in Canada, nor any mainstream politician in the United States, openly advocates annexation. Two minor provincial political parties in Canada promoted the concept in the 1980s, but neither attracted widespread support or attention. Historical annexationist groups 1837 Historical annexationist movements inside Canada were usually inspired by dissatisfaction with Britain's colonial government of Canada. Groups of Irish immigrants took the route of armed struggle, attempting to annex the peninsula between the Detroit and Niagara Rivers to the U.S. by force in the minor and short-lived Patriot War in 1837–1838. Although the Rebellions of 1837 were motivated in part by this type of dissatisfaction, Canadian resentment of British rule never reached the degree that led to the American Revolution in 1775. Notably, Canada's population growth in the late 18th and early 19th centuries was spurred largely by United Empire Loyalists, who left the American colonies during the Revolution because of their loyalty to Great Britain. In the period from 1790 to 1837, imperial officials repeatedly denounced American-style republicanism and tried to suppress it. The Rebellions themselves were not fought with the goal of annexation, however, but were launched in pursuit of political independence from Britain and liberal social reforms. Between 1848 and 1854, a significant and articulate minority of conservatives in Upper Canada advocated constitutional changes modelled on the American federal-state system and the US Constitution. They critiqued Canada's imitation of