There was pretty good cooperation between the American Army and the Royal Canadian Mounted Police on the frontier.  They helped each other whenever they could, or at least when the benefits outweighed the negatives.  During this era, the main problems were the miscreants from either nation crossing the border for nefarious purposes such as stealing horses.  Another was trying to control the endless river of whiskey crossing the border for trade to local Indian tribes or whoever.  It ultimately meant chaos and disruption of the purely idyllic atmosphere of frontier life for everyone.  In this painting, a contingent of the US Army is seen driving a herd of stolen horses back across the Border to the loving care and possession of the Mounties.   This act will almost satisfy the craving for revenge by the victims and but may only delay that type of criminal activities for a day.

But it was the right thing to do.