As war with the United States loomed in 1809, the Governor-General of Canada secretly hired a shady Vermonter named John Henry to evaluate the attitude of New Englanders toward secession and reunion with Britain. Henry wrote a series of encouraging letters, mostly gleaned from newspaper reports and barroom talk. In the end, the British refused to pay him.
Three years later he took his revenge by selling his correspondence with the Governor-General to President Madison for fifty thousand dollars.
The antiwar Federalist party mocked: "The Henry Papers, bought and sold, and paid for with the nation's gold."
The revelation of Britain's duplicity did much to push America into a war for which it was poorly prepared.