The advance turned to war in 1846, and after the United States conquered the provinces, once considered the limits of American growth, a vast expanse of territory reveals the nation`s ugliest differences: what to do about slavery? Adams and Ones negotiated the final agreement, but the issues between their two nations date back to the early days of the American Republic. The treaty remained in full force for only 183 days: from 22 February 1821 to 24 August 1821, when Spanish military signed the Treaty of Cordoba recognising Mexico`s independence; Spain rejected this treaty, but Mexico did take control of the former Spanish colony. The border treaty between Mexico and the United States, signed in 1828 and entered into force in 1832, recognized the border defined by the Adams-Ons Treaty as a border between the two nations. Adams said the United States should take control because Florida (along the Georgia-Alabama border) had become «a dilapidated man open to the occupation of any enemy, civilized or savage, of the United States and which had served no other earthly purpose as a post of irritation for them.» [8] [9] Spain requested British intervention, but London refused to support Spain in the negotiations. Some members of President Monroe`s cabinet called for Jackson`s immediate dismissal because of the Florida invasion, but Adams realized that his success had given the United States a favorable diplomatic stance. Adams was able to negotiate very favourable terms. [7] The agreement was officially known as the Treaty on Amity, Settlement and Borders between the United States of America and its Catholic Majesty. [2] Today it is more often referred to as a transcontinental contract to emphasize its geographical scope, or it is known as the Adams-Ones Treaty, according to its two architects, Secretary of State Adams and Spanish Attorney Minister Luis de Ones. [3] The United States claimed essentially the same region on the basis (1) of Robert Gray`s voyage to the Columbia River in 1792, (2) the U.S. Lewis and Clark Expedition of 1804-1806 and (3) the founding of Fort Astoria on the Columbia River 1811. On October 20, 1818, the Anglo-American Convention of 1818 was signed, which established the border between British North America and the United States east of the continental axis along 49. and a common Anglo-American occupation west of the Great Divide.

The Anglo-American agreement ignored the Nootka Convention of 1794, which gave Spain common rights in the region. The convention also ignored Russian settlements in the region. The United States called this region Oregon Country, while the United Kingdom called the district district of Columbia.