How did reciprocity affect the confederation?

Reciprocity, which means free trade, between the US and Canada, would help Canada's economy considerably. However, when Canada's mother country, Britain, supported the SOUTH side, the LOSING side to the American Civil War, the Americans (the NORTH side, who won) cancelled reciprocity as revenge on Britain for unofficially supporting the South. With Confederation, Canada would be independent from Britain, and therefore, the Americans could not do things to CANADA as revenge on BRITAIN. :)