Controversial Canadian Events 1867-1939

I wish to do a project on Canadian history, being a Canadian myself. However, so many things are no longer taught in high schools, that I'm only beginning to learn about in university.

For my project, I want to explore an event that is controversial, but clearly has scholarly support for both sides of the argument. I've been trying to do research, but every event I find seems to be very united in terms of opinion. I'd really like to spice things up with controversy, one that historians still can't agree on today.

We are studying events of 1867-1939, so I require the event to be linked to this. Or, even if it's a more modern event, it is tied to this (For example, the burning of effigies of John A. Macdonald).

Any suggestions?

Thanks!

EDIT: Thank you for all the suggestions, this was the type of stuff I was looking for. Provided lots of inspiration!