Defense vs. Defence in Canadian English

I recently came across this spelling of "defense/ce" in a Canadian newspaper:

Canada is a close U.S. military ally and the top U.S. export market, more than the U.K., Japan and Germany combined. It sells the U.S. more steel and aluminum than anyone else, in part because of deeply integrated auto and defense sectors [emphasis added]."

(http://business.financialpost.com/news/economy/trump-appeasement-fails-so-trudeau-takes-the-gloves-off)

According to all dictionaries I have looked at, defense is solely an American spelling, and the spelling defence is officially used in Canada.

My question is this: Are there any Canadians, or people familiar with Canadian English, that can comment on whether the defense spelling is also common in Canada, or whether this example is simply a one-off? I have so far been unable to find any sources that confirm any occasional use of the -se spelling of defense in Canadian English. I have a hunch that The Canadian Oxford Dictionary might have something to say on this, but I do not have access to it.

Solution 1:

I'm Canadian and work with Canadian editors.

The Canadian Oxford Dictionary (2nd ed.) often provides both British and American spellings of words. Sometimes the British spelling comes first, and other times it's the American spelling that comes first. (It's not actually true that we always prefer one over the other.)

In all cases, the one that's listed first is more common that the other—but both are "correct."

It's the house style of any particular publisher that determines what's used for their publications. Many Canadian publishers and companies decide that if a word has both British and American variations, it's the first variation that should be used. But it's not a universal decision—and it's only a matter of style, not of a single dictionary entry.

Defence is not the sole official spelling of the word in Canada—defense is also an official spelling in Canada.

However, it's the style choice of Canadian government publications to only use defence—which is something quite different.

From the Canadian Oxford Dictionary (2nd ed.):

de·fence/dɘ'fens/noun (also de·fense)

de·fence·man (noun) (pl -men) (esp. US de·fense·man)

Software that uses Canadian English dictionary rules should (and commonly does) mark both spellings as correct.

I suspect that the use of defense in the National Post was an unintentional typo. While still in the dictionary, it's likely that it goes against their house style and simply went unnoticed.

I should add that many people, in less formal settings, frequently do use the secondary spelling of many of these words as a matter of personal choice.

Solution 2:

Canadian newspapers, however, do have an official style guide: The Canadian Press Stylebook, supplemented by The Canadian Press Caps and Spelling. It says "defence (not defense), but defensive."

The editor insisting on c for nouns and s for verb forms is following CP style: "practice (n. or adj.), practise (v.)"