Quite some time back, it struck me that Canada is a tenuous construct. The occasion for that insight was realizing that what I like most about Canada as a “state” is the fact of its precarity. The wobbly prop at the prominent corner is Quebec. No a mari usque ad mare without getting across Quebec! Therefore no need to suffer rot about one nation indivisible. The wobbly prop at another corner is that weird opening to the anthem: O Canada, our home on native land [subtly emended in the interests of truthtelling].
This is all preamble to a pointer to a book review with a map that suggests how messy North America is, how artificial that 49th parallel is, and how fabricated the 145-year-old northern ex-colony is. Provocative, n’est-ce pas?
Never forget that all Canada has done for US extraterritorials is to reread the tax treaty and to reiterate what already happens to be there. Sort of like most of what the IRS manages to come up with after the ambassador tells grannies to sit tight.

