“The movement to join Washington had a substantial following in the 1850s, centred in Montreal...It faced considerable resistance, though - in part because the United States was having one of its periodic convulsions of nativist politics and a furious debate over the slave trade. In fact, the U.S.-annexation movement would receive its final rebuff not from colonial-minded Canadians but from the Confederate states, who feared that the addition of the British North American colonies to the 31 states would tip the political balance of power away from slavery.”