To the Secretary's office, one day in June, 1818, came a letter from De Onis which was a veritable firebrand. De Onis, who was not unnaturally disposed to believe the worst of Americans on the border, had heard that General Andrew Jackson in pursuit of the Seminole Indians had crossed into Florida and captured Pensacola and St. Mark's. He demanded to be informed "in a positive, distinct and explicit manner just what had occurred"; and then, outraged by confirmatory reports and without waiting for Adams's reply, he wrote another angry letter, insisting upon the restitution of the captured forts and the punishment of the American general. Worse tidings followed. Bagot, the British Minister, had heard that Jackson had seized and executed two British subjects on Spanish soil. Would the Secretary of State inform him whether General Jackson had been authorized to take Pensacola, and would the Secretary furnish him with copies of the reports of the courts-martial which had condemned these two subjects of His Majesty? Adams could only reply that he lacked official information.
By the second week in July, dispatches from General Jackson confirmed the worst insinuations and accusations of De Onis and Bagot. President Monroe was painfully embarrassed. Prompt disavowal of the general's conduct seemed the only way to avert war; but to disavow the acts of this popular idol, the victor of New Orleans, was no light matter. He sought the advice of his Cabinet and was hardly less embarrassed to find all but one convinced that "Old Hickory" had acted contrary to instructions and had committed acts of hostility against Spain. A week of anxious Cabinet sessions followed, in which only one voice was raised in defense of the invasion of Florida. All but Adams feared war, a war which the opposition would surely brand as incited by the President without the consent of Congress. No administration could carry on a war begun in violation of the Constitution, said Calhoun. But, argued Adams, the President may authorize defensive acts of hostility. Jackson had been authorized to cross the frontier, if necessary, in pursuit of the Indians, and all the ensuing deplorable incidents had followed as a necessary consequence of Indian warfare.