A US citizen received an income tax assessment letter from Canada
Revenue, claiming that income tax is owed to Canada from a few years
earlier.  The duration of
work in Canada, and circumstances of work make it unclear if there is any tax
liability for Canada.  The question is: can/will Canada collect from a
US citizen in the US through any court action, including civil court,
tax court, or criminal court, or is there any other method for Canada
to collect from this US citizen?