In the year 1818, in the course of what is known as the Seminole War, General Jackson, at the head of a strong body of troops, invaded the Spanish territory of Florida, captured a number of fortified places, and ruthlessly hanged one British subject named Arbuthnot and shot another named Ambrister on the unproved charge that the two had been "stirring up the Indians to war with the United States." No war followed this outrage, but the ill feeling which had animated the British after the War of 1812 was greatly intensified.
Trouble over the northeast boundary of the United States followed, and when the king of the Netherlands was asked to arbitrate the matter, he laid down a line which was not satisfactory to the English. At the same time it was exasperating to the Americans, especially to the people of Maine. In fact, open hostilities in a small way occurred near the boundary.
In 1837 the British manner of ruling the Canadian region created so much opposition among the settlers there that a small insurrection broke out. It was suppressed, but only to break out again, and at this time a number of American sympathizers joined the insurgents. A band of the insurgents having taken possession of Navy Island, in the Niagara River, the American sympathizers went in the American steamer Caroline to join them, and carried arms and supplies. The steamer then returned to American waters, but the British loyalists crossed over the line, captured the steamer, set her on fire, and sent her over Niagara Falls. One American was killed in the attack. Later a Canadian deputy sheriff boasted that he had killed the man whose life was taken, and then, in 1840, incautiously came across to Lockport, New York, where he was arrested for the murder. His name was Alexander McLeod. Thereupon the British government, with the aggressive Palmerston in the lead, avowed that the Caroline was seized on the authority of the nation, and peremptorily demanded McLeod's release. The Washington authorities were disposed to yield, but Governor Seward, of New York, declared that McLeod should stand trial; and he did. But having proved an alibi, he was acquitted, and on October 12, 1841, he was returned to Canada. In the meantime an American had been seized as a hostage to abide McLeod's fate. He was of course released at last.
In the course of the year 1841 an American coaster named the Creole, while carrying a cargo of slaves from the breeding grounds in Virginia to the ever eager market in the Southwest, was taken from her officers and crew by the slaves, who then ran the vessels to the Bahamas, where the slaves, 125 in number, were protected. The slave owners of the United States had been restive because of frequent reports that British cruisers, engaged in suppressing the slave trade upon the coast of Africa, had "exercised the right of search" by boarding ships under the American flag, and when the story of the protection of the Creole's cargo reached the country, the excitement rose toward the war heat.
In the meantime, the United States had annexed Florida. Then the Texans set up an independent government, and it was recognized as an independent nation, but with its people openly anxious for annexation to the United States. The statesmen of England saw that annexation was inevitable and that a war with Mexico would follow, with the result that the territory of the United States would be enlarged in the Southwest and along the Spanish Main, where British subjects were looking for a further extension of territory and influence. For at about this time the ancient settlement of logwood cutters at Belize was developed into the colony of British Honduras (1845). Although England had subscribed to and helped to enforce the Monroe Doctrine, her statesmen were looking to an extension of British Honduras as far south as the mouth of the Rio San Juan, in Nicaragua. To secure this extension a protectorate over the Mosquito Coast Indians was declared, and the coast was assumed to be territory entirely independent of Nicaragua. On August 19, 1841, British war-ships captured San Juan del Norte, at the mouth of the San Juan, drove away the Nicaragua officials, and installed Mosquito Indians. The Nicaraguans soon drove away the Mosquito forces, but the interest in the place having been intensified by projects for building an interoceanic canal across the country, the British returned, late in 1847, and on January 10, 1848, placed the Mosquito chiefs once more in possession.
With the rush of emigrants to California, the United States became interested in this aggression. It would never do to allow the British to control such a highway as was then in contemplation. The British naturally held on to what they had secured at the mouth of the San Juan, however, and then, with a view of obtaining control of the other end of the canal route (the Gulf of Fonseca), they began to press Honduras for the payment of certain claims of British subjects, the nature of which is of no importance because the claims were merely a pretext for an aggression that would have been made had no claims been in existence. To back these claims a British warship appeared, but when the Honduranians were in straits, the American envoy to Nicaragua heard of their trouble, hastened to meet them, and then negotiated a treaty (September 28, 1849) by which a part of Tigre Island and a part of the coast of the Gulf of Fonseca were granted to the United States for a naval station. When the British envoy learned how he had been outwitted, he ordered some of the naval force at his command to seize Tigre Island in contempt of the acquired rights of the United States. (See Keasbey's Nicaragua Canal and Pims Panama.) That the British fully expected a war with the United States, is beyond dispute. In fact, they had been prepared for war ever since 1840, but the Nicaragua matter it was supposed would surely bring on the long-looked-for contest.
To add to the dangers of the situation, a dispute had arisen, meantime, over the northwestern boundary of the United States, a controversy commonly referred to in history as the Oregon Question. The United States claimed the territory as far north as the south line of Alaska, then belonging to Russia, in latitude 54° 40'. The British claimed as far south as the Columbia River. The claims created great excitement in this country in 1845, and the cry of "Fifty-four forty, or fight" was heard throughout the nation.
To show the state of feeling in England at that time, here is a quotation from a letter written by Louis McLean, American Minister to London, to the Secretary of State, January 3, 1846.
"I sought an interview with Lord Aberdeen, in order that, in conformity with your instructions, I might bring to his notice the warlike preparations making by Great Britain, and, if possible, ascertain their real character and object.... In introducing the subject I adverted at the same time to the information the President had received from various sources, of the extensive preparations making by Great Britain, and the natural inference upon his part that, in the present pacific state of the relations of Great Britain with all the powers of Europe, they could only look to a rupture with the United States.... Lord Aberdeen said very promptly and frankly that it would be improper to disguise that, with the sincerest wish to avoid it, they were obliged to look to the possibility of a rupture with the United States, and that in such a crisis the warlike preparations now making would be useful and important.... He stated that the most extensive and formidable parts of their preparations were the fortifications of the principal and exposed stations ... and to the increase of the number of steam vessels in lieu of the old craft." (See Cong. Globe, February 6, 1847.)
In short, during the whole period under consideration, the Americans and the British were constantly animated by intense antipathy and even animosity, each toward the other.