Nils von Schoultz was born Nils Gustaf Ulric in 1807 in Finland. He fought in the Polish revolution of 1830, was captured by the Russians, but somehow escaped to join the French foreign legion. After a brief marriage to a British woman, in 1836 he changed his name to von Schoultz and moved to the United States.
The next year saw short-lived republican uprisings in both Upper and Lower Canada (Ontario and Quebec). The Upper Canadian revolt led by William McKenzie, in particular, had little real base of support, but it was hard to get Americans to understand that. Steeped in the thinking of Michael Gerson, they thought it obvious that any people under the British Crown would want a revolution. They greeted McKenzie and his band with open arms, and organized bands of revolutionaries to "liberate" Canada. One such, based in Cleveland, was called the Hunters' Society, which held its first and only convention on September 16, 1938, resolving to use armed struggle to free the Canadians from the not-very-oppressive yoke of Queen Victoria and the Colonial Office.
With the memories of 1812 still fresh, the royalist pro-colonial Upper Canadians responded by organizing their own militias. An obscure Kingston lawyer named John Macdonald joined one of them, the "Loyal Scotch Volunteer Independent Light Infantry Company." (As Max Shachtman once remarked about Trotskyist sects, the length of the name is always in inverse proportion to the size of the group).
As Donald Creighton relates, "[U]nder the emphatic but dubious instruction of the Hunters, [von Schoultz] reached the romantic conclusion that the Canadians were serfs groaning under an oppression indistinguishable from that of the Poles." On November 11, 1838, he and 180 others boarded the steamer The United States and crossed Lake Ontario.
The ostensible leaders of the expedition decided not to disembark. The skipper Bill Johnston, who took the title Commodore of the Navy of the Canadian Republic, insisted that his duty was with the fleet, while the "commander" of the land forces, John Birge, claimed intestinal distress. Von Schoultz found himself leading the invading army. They landed at Windmill Point near Prescott and took the eponymous windmill. This gave them a certain tactical advantage when they were attacked by the Johnstown Militia (with a small number of redcoats in support). 60 Canadians were wounded and 16 killed, among them the commander Lieutenant Johnston, whose body was mutilated, much to the indignation of Upper Canadian opinion. But the invaders were eventually surrounded and surrendered.
The leaders, including von Schoultz, were court martialed under a colonial statute, An Act to Protect the Inhabitants of this Province against Lawless aggressions from the Subjects of Foreign Countries at Peace with Her Majesty, 1 Vic. c.3. The statute provided hanging for citizens of foreign countries at peace with Britain who associated themselves with traitorous and rebellious British subjects and made war against the Queen slaying or wounding divers of Her Majesty's subjects.
The court martial procedure did not allow for defence counsel, but civilian lawyers were allowed to assist the accused in defending themselves. John A. Macdonald, then 23, was asked to do so by a Canadian relative of one of the defendants. As can be imagined, it was not a popular cause in Tory Kingston. But Macdonald decided to take it on. As Creighton put it:
It was a difficult, unprofessional, unpopular and possibly dangerous task. In a court martial, bereft of his usual status and prerogatives, [Macdonald] would be a nobody in an alien and perhaps hostile world. It would be almost impossible for him to secure an acquittal, or even to mitigate the death sentence, for the statute was clear and comprehensive enough, and the prisoners had been caught red-handed. Yet even an ineffectual defence might arouse the whole community against him. The prisoners were hated, as only foreigners who interfere by force in the affairs of others can be hated. The town was mad with grief and rage and horror. The futile enormity of the invasion itself, the long, needless list of dead and wounded at the Battle of the Windmill, the revolting mutilation of Lieutenant Johnston's body, and the heap of carved, double-edged bowie knives which had been taken from the Bandits and exhibited to the astounded Kingstonians -- all worked like madness in the minds of the townspeople. Every circumstance seemed unfavourable. It was surely wisdom to have nothing to do with the whole affair. And yet, he took the case. Even he might have found it difficult to say why. A curious interest in people, a relish for cases which were odd and difficult, a jaunty recognition of the fact that professional prestige involved publicity, and, perhaps, a certain stubborn, independent conviction that these helpless and deluded men deserved at least the bare minimum of assistance -- all these may have helped to move him to his decision.
Macdonald was not able to save von Schoultz. Over the warnings of the Judge-Advocate (who was also the Solicitor General of the Province), von Schoultz pleaded guilty. His main concern was to deny that he had any involvement in the shameful mutilation of the opposing commander's body. He was immediately sentenced to hang. Macdonald drafted his will. According to Creighton, Macdonald referred to his experience with von Schoultz for the rest of his life, including in a letter written shortly after the hanging of Riel.
Update: Ella Pipping wrote a biography of von Schoultz, which is out-of-print and which I haven't read. Here is Wikipedia's article on the Battle of the Windmill.
Google also provides the charming news that Kathleen Herron, a Grade 6 student at Rideau Public School, penned these lines in celebration of John A's willingness to champion the marginal:
Nils Von Schoultz, a Swedish man
Barking mad and on the loose
Attacked our great Canadian land
Soon was forced to face the noose
A fiery defender of the underdog
The underdog, the underdog
A fiery defender of the underdog
The wee John A.
Someone give that girl a grant!