Oh brother.
"Only the US corporate media continued to peddle them, ignoring all the evidence contradicting them".
The "corporate media"? Which media is that again? NBC? CNN? All of those staunch "conservative" leanings?  LOL. 
BTW - all of the "evidence" in dispute was after the fact, not prior. Hindsight is 20-20 and let's face it, that's where your views originate. And quite frankly, NO ONE on the south side of the border expected support from Canada, so it was not a surprise.