Canada provides natural resources to the US (oil, lumber, etc.) and imports manufactured goods.

In 2009 73% of Canada's exports went to the United States, and 63% of Canada's imports were from the United States.[34] Trade with Canada makes up 23% of the United States' exports and 17% of its imports.[35] By comparison, in 2005 this was more than U.S. trade with all countries in the European Union combined,[36] and well over twice U.S. trade with all the countries of Latin America combined.[37] Just the two-way trade that crosses the Ambassador Bridge between Michigan and Ontario equals all U.S. exports to Japan. Canada's importance to the United States is not just a border-state phenomenon: Canada is the leading export market for 35 of 50 U.S. states, and is the United States' largest foreign supplier of energy.

The economy of the smaller country (Canada) is much more dependent on the economy of the larger country (US) than vice versa. The US is significantly more powerful on the global political and economic stage than Canada. The same economic and political relationship will likely emerge with an independent Scotland. The northern country is heavily integrated with the globally significant southern country.