On July 12, 1812, Brigadier General William Hull initiated the first military campaign of the War of 1812, calling for--and attempting--an invasion of Canada. Unfortunately for Hull, it was an utter disaster--his assumption that Canadians would side with American forces against the British proved terribly wrong, and his rather arrogant proclamation to Canadians that they would "be emancipated from Tyranny and oppression and restored to the dignified status of freemen" failed to impress. Shortly after marching his troops across the border, he retreated back across the border, surrendering at Detroit on July 16th.
Further reading in our collections:
Maria Campbell Hull, Revolutionary Services and Civil Life of General William Hull; Prepared from his Manuscripts, by his Daughter, Mrs. Maria Campbell: Together With the History of the Campaign of 1812, and Surrender of the Post of Detroit, By His Grandson, James Freeman Clarke (New York, 1848).
William Hull. Memoirs of the Campaign of the North Western Army of the United States, A.D. 1812 (Boston, 1824).
E. Cruikshank. General Hull's Invasion of Canada in 1812 (Ottawa, 1907).