Practically? Yes. Canada is pretty much already an American province and most Canadians live within 100km of the US, let alone you will find that even more live in the major metropolitan areas around Vancouver, Toronto, or Montreal/Quebec. Canada is already heavily integrated into American supply lines (really they should be called North American supply lines), so it would make little difference there, frankly. Culturally, sans Quebec, Canada is largely the same country. There are certainly regional differences, but you have more cultural differences between the south and the north, than you do with the north versus Canada. Vancouver and BC is basically an extension of Washington (aka, the broader Cascadia region), Alberta is an extension of Montana, Ontario is similar to Illinois, Pennsylvania, upstate New York, etc (Laurentia).
Saying that, no, they likely could never merge.
Its a hard set thing in the Canadian identity that they are not American, nor should they unite politically with America. Canadians, even if they go into Washington or NY, imagine most of the US to be Texas. There is a smugness about many Canadian's views of the US, and even though in practical terms there are few differences, Canadians will insist that there are.
