The Governor General is the only one who can remove Harper. If the Conservative caucus were to revolt and kick Harper out of caucus, we could be faced with Stevie-the-Indie-PM. Even if Harper resigns -- which isn't likely -- it is still the GG who chooses to accept.
The international community marked the 197th anniversary of the birth of Canada's first Prime Minister, John A. Macdonald, by completely ignoring the man as well as the country he headed. Despite proximity to Canada, Americans seemed no likelier to understand references to Macdonald.