"The acquisition of Louisiana terrified many Federalists, who feared that the creation of new western states would further dilute their political influence. In the winter of 1803-1804, a group of Federalist congressmen plotted to establish a "Northern Confederacy" consisting of New Jersey, New York, New England, and Canada, to be established with the support of Britain." - Digital History
So my History teacher recently talked about this and it made me ponder how would the world change if the Northern Confederacy came to be, IF it could. The most likely way of them doing it is during the War of 1812, but it would be interesting to see other ways in doing so.
http://www.digitalhistory.uh.edu/disp_textbook.cfm?smtID=2&psid=2984