Whilst researching stuff on the Infallible Wikipedia, I learned that there was a significant Anti-Confederation Movement in Canada, primarily in the Maritimes, that rejected the Canadian Confederation that would hold its first elections in 1876.
OTL, the Anti-Confederates only won the vote in two provinces (Nova Scotia and Newfoundland) and failed to win New Brunswick, the only other province with a significant secessionist feeling. Newfoundland was excluded from Confederation, only joining Canada in the 20th century, but London flatly warned Nova Scotia against trying anything stupid and the Anti-Confederates essentially gave up, blending into the mainstream Liberals and Conservatives a few years later.
Now, could this have turned into a Canadian Civil War (or perhaps rebellion is a more accurate term) if the Anti-Confederates had done better in New Brunswick? The Maritimes vs. Upper and Lower Canada?