Perhaps they ought to arm themselves with the fact that America has fought more wars with Canada than with any other country: the War of the League of Augsburg (1689-1697), the War of the Spanish Succession (1701-1714), the War of the Austrian Succession (1744-1748), and the Third Silesian War (1754-1763), as well as the War of the American Revolution and the War of 1812.
One could therefore argut that Canada is America's traditional enemy--even though in the first four of these wars, we were English and they were French, and in the last two, they were English.
Actually, the U.S. and Canada have never fought a war aganst each other. Canada didn't exist as a country until 1867. Any conflicts that did occur were against the British in British territories, or other powers, but not Canada. The U.S. and Canada have been either allies or friends for most of the life of Canada. Also, some of the wars you described were not fought by America, either, since the U.S.A. did not come into existence until 1776. Those wars were fought in colonial North America by European powers.