During the political conflicts in Canada in the 1800s, Canada asked America for his help, but because America was expanding and trying to hold his own country together he couldn't. America's bosses made him put up a neutrality border, and neither brother could cross it for years. It was much like the Berlin Wall that separated Germany and Prussia except the two could see each other. Many times, one would be near the border and the other would come to visit, but they couldn't say anything to each other without getting into trouble with their bosses. All America could do was mouth I'm sorry Canada from his side of the border.
*If you don't know what I'm referring to, Canada went through major political rebellions before being one nation. America was asked for help, but this was around the time of the Mexican wars and when America was expanding west, so they really couldn't help. America put a neutrality border up, and it was illegal to cross into either country. That's just a short summary. If I missed anything or messed anything up, I'm sorry. I'm not Canadian, so most of this information came from a Google search I made my friend do for me.*