Alexander McLeod

Alexander McLeod was a Scottish-Canadian who served as sheriff in Niagara, Ontario. After the Upper Canada Rebellion, he boasted that he had partaken in the 1837 Caroline Affair, the sinking of an American steamboat that had been supplying William Lyon Mackenzie's rebels with arms. Three years later, he was arrested by the United States and charged with the murder of the sailor killed in the attack, but his incarceration infuriated Canada and Great Britain, which demanded his repatriation in the strongest terms; arguing that any action taken against the Caroline had been taken under orders, and the responsibility lay with the Crown, not McLeod himself.

President Martin van Buren ignored the demands for repatriation, leading Lord Palmerston to threaten that a continued refusal to repatriate McLeod would result in "war immediate and frightful in its character, because it would be a war of retaliation and vengeance".

McLeod was tried in a "curious spectacle". He was acquitted on the basis of an alibi that supported his non-participation in the Affair.