Answer:
The US and Canada should not merge into one large country due to the fact that they have very distinct forms of government and culture. Canada is much more left in their ideals on a global scale, whereas the US is more right. This would lead to several conflicts. Not to mention, Canada is still part of the British Commonwealth, so they would have to break apart from that in order to join the US. Finally, a large part of Canada speaks French and operates in French, they would be a culutral and language barrier between this section of Canada and the US.
Explanation: