SCP Foundation

The Great Northern War, a conflict between the US and Canada. The Conflict begins with an incident of an attempted assassination of the US president from a "former" Canadian intelligence agent, due to the attempt and connection with the Canadian government, US forces move north to Canada. The US uses some anomalies from the Foundation through the approval of the O5 council. The wars combatants are the US, Canada, Russia, UK, France, Germany and several other small NATO countries.

First thing, to have a canon you need at least three writers writing at least five sucessfull articles, so you cannot build a canon on your own. What you could do on your own is writing a series, as in a series of Tales or SCPs or both.

Second, okay you have a war. What does it have to do with the Foundation? Why would a war between them concern the Foundation at all? Why would the Foundation take sides in this war? And especially, why would they aid USA who have plenty of non-anomalous resources and second largest nuclear stockpile in the world, while Canada has none? America could stand and fight their own war just fine without Foundation aid, and the Foundation has no business intervening in the war that doesn't concern the anomalous. Call the UN for that, not the hypersecret anomaly-containing organization.

The way you phrased it, it sounds almost like the Foundation Universe was added as an afterthought to the concept, instead of the setting for the entire story. The way that the Conflict started also doesn't really make sense. Canada has no reason to assassinate USA president, in fact under the threat of heavy and swift retaliation, it is within their best interest to keep at least neutral stance to the American government.