The British government avowed this invasion to be a public act and a necessary measure of self-defence; but it was a question when Mr. Van Buren went out of office whether this avowal had been made in an authentic manner.  There was another incident, however, also growing out of this affair, even more irritating and threatening than the invasion itself.  In November, 1840, one Alexander McLeod came from Canada to New York, where he boasted that he was the slayer of Durfree, and thereupon was at once arrested on a charge of murder and thrown into prison.  This aroused great anger in England, and the conviction of McLeod was all that was needed to cause immediate war.  In addition to these complications was the question of the right of search for the impressment of British seamen and for the suppression of the slave-trade.  Our government was, of course, greatly hampered in action by the rights of Maine and Massachusetts on the northeastern boundary, and by the fact that McLeod was within the jurisdiction and in the power of the New York courts, and wholly out of reach of those of the United States.  The character of the national representatives on both sides in London tended, moreover, to aggravate the growing irritation between the two countries.  Lord Palmerston was sharp and domineering, and Mr. Stevenson, our minister, was by no means mild or conciliatory.  Between them they did what they could to render accommodation impossible.

To evolve a satisfactory and permanent peace from these conditions was the task which confronted Mr. Webster, and he was hardly in office before he received a demand from Mr. Fox for the release of McLeod, in which full avowal was made that the burning of the Caroline was a public act.  Mr. Webster determined that the proper method of settling the boundary question, when that subject should be reached, was to agree upon a conventional and arbitrary line, and that in the mean time the only way to dispose of McLeod was to get him out of prison, separate him, diplomatically speaking, from the affair of the Caroline, and then take that up as a distinct matter for negotiation with the British government.  The difficulty in regard to McLeod was the most pressing, and so to that he gave his immediate attention.  His first step was to instruct the Attorney-General to proceed to Lockport, where McLeod was imprisoned, and communicate with the counsel for the defence, furnishing them with authentic information that the destruction of the Caroline was a public act, and that therefore McLeod could not be held responsible.  He then replied to the British minister that McLeod could, of course, be released only by judicial process, but he also informed Mr. Fox of the steps which had been taken by the administration to assure the prisoner a complete defence based on the avowal of the British government that the attack on the Caroline was a public act.  This threw the responsibility for McLeod, and for consequent peace or war, where it belonged, on the New York authorities, who seemed, however, but little inclined to assist the general government.  McLeod came before the Supreme Court of New York in July, on a writ of habeas corpus, but they refused to release him on the grounds set forth in Mr. Webster’s instructions to the Attorney-General, and he was remanded for trial in October, which was highly embarrassing to our government, as it kept this dangerous affair open.