In fact, given its entanglements with their southern counterparts the Canadian Forces would likely enable a US invasion. As with the 2003 invasion of Iraq — which Ottawa officially opposed — some Canadian troops on exchange in the US might march north and, as is the norm when the US invades another country, Canadian officers would likely operate NORAD systems aiding the aggression.
That's a pretty bold opinion with absolutely nothing to back it up. There's a massive difference between supporting an army invading Iraq, and invading your own homeland.