In June, 1818, Mr. Richard Rush, who owed his introduction into public life to Mr. Gallatin, was appointed minister to England, Adams returning to the United States to take the portfolio of State in President Monroe's cabinet. Gallatin was joined to Rush, for the conduct of negotiations with Great Britain, rendered necessary by the approaching expiration of the commercial convention of July 3, 1815, which had been limited to four years. The general field of disputed points was again entered. It included the questions of impressment, the fisheries, the boundaries, and indemnity for slaves. The commissioners were supported by a temper of the American people different from that which prevailed when Jay and Gallatin respectively undertook the delicate work of negotiation in 1794 and 1814. A compromise was arrived at, which was signed on October 20, 1818. The articles on maritime rights and impressment were set aside. A convention was made for ten years in regard to the fisheries, the northwest boundary, and other points, and the commercial convention of 1815 was renewed. The English claim to the navigation of the Mississippi was finally disposed of, and the article concerning the West India trade was referred to the President. The arrangement of the fishery question disturbed Mr. Gallatin, who found himself compelled to sign an agreement which left the United States in a worse situation in that respect than before the war of 1812. But as the British courts would certainly uphold the construction by their government of the treaty of 1783, our vessels, when seized, would be condemned and a collision would immediately ensue. This, and the critical condition of our Spanish relations, left no choice between concession and war. A short time afterward Lord Castlereagh and the Duke of Wellington expressed friendly dispositions, and the mooted points of impressment and the West India trade were considered by them to be near an arrangement. The right of British armed vessels to examine American crews was abandoned in the convention itself.
In July, 1818, the capture of Fort St. Mark and the occupation of Pensacola in Florida by General Jackson made some stir in the quiet waters of our foreign diplomacy. Uncertain as to whether the act would be disavowed or justified by the American government, Mr. Gallatin explained to the European ministers that the forcible occupation of the Spanish province was an act of self-defence and protection against the Indians, but Richelieu replied that the United States "had adopted the game laws and pursued in foreign ground what was started in its own." Yet, to the astonishment of Mr. Gallatin, Richelieu was moderate and friendly in language, and urged a speedy amicable arrangement of differences with Spain, in whose affairs France took an interest, and who had asked her good offices. But Gallatin at once rejected any idea that the United States would join France in any mediation between Spain and her revolted colonies. It seems rather singular that, to the suggestion that a Spanish prince might be sent over to America as an independent monarch, Gallatin contented himself with expressing a doubt as to the efficacy of such a course to preserve their independence. Mr. Adams was informed that public recognition of the independence of the insurgent colony of Buenos Ayres would shock the feelings and prejudices of the French ministers, but that notwithstanding this displeasure, France would not join Spain in a war on this account. England, however, would see such a war without regret, and privateers under Spanish commissions would instantly be fitted out, both in France and England. Under the existing convention with Great Britain three hundred American vessels arrived at Liverpool in the first nine months of 1818 from the United States and only thirty English, an advantage to the United States which war would at once destroy. Russia also was displeased with the recognition of the independence of the Spanish colonies. At the Congress of Aix la Chapelle various plans of mediation were proposed, but England refusing to engage to break off all commercial relations with such of the insurgent colonies as should reject the proposals agreed to, the whole project was abandoned. An agreement between the five great powers for the suppression of the slave trade was also proposed at this Congress, but France declined to recognize the right to visit French vessels in time of peace, and Russia making a similar declaration, this plan also fell to the ground, and even an association against the exactions of the Barbary powers was prevented by jealousy of the naval preponderance of Great Britain.