The Ontarian Liberation Army is actually only such in name; a sort of homage to their ancestors, who fought the American annexation of Canada before the Great War. Those that survived did so in the isolation and solitude of the far North of Canada, where they remained untouched from the nuclear fire that rained down on the rest of the world.
So far as they are concerned, Canada is a sacred land. Though occasionally harassed by the hockey-geared gangs of the Great White North, they have few enemies. None so great as the Evil Americans to the South. Since the Great War, their ancestors have passed down stories of the horrible acts committed upon them by the American menace. As such, most citizens of the "Army" harbor a mix of fear and hatred towards America.
For the most part, they keep to themselves, though they have been known to offer aid to smaller groups in the wasteland. As far as post-apocalyptic civilizations go, this one is a fairly nice one. The people are mostly friendly, often having a sort of open-arms attitude, and live under a sort of light-touch democracy, headed by a Prime Minister, who is selected by the people of the "Army", and serves for a term of five years.
Though satisfied to remain on the Canadian side of the border, the Ontarian Liberation Army has sent several recon forces onto United States soil. As such, other civilizations, such as the Niagara Republic, have had contact with them in the past. As far as the Republic is concerned however, the "Army" as inefficient and powerless, as they do not share the same harsh system of brutal law enforcement and military doctrine as they do.
In 2264, the Ontarian Liberation Army launched a small military campaign against the "American Heretics" inhabiting Niagara Falls, led by Commanding General Orson Fischer. After a long, and drawn out battle, the two sides admitted a stalemate, and returned home, with a few utterances of "sorry" (at least from the Canadians).
Since then, the two factions have had a sort of uneasy truce, and continue to watch each other closely, and on high alert, just in case. As of 2277, neither side has really done anything, though.