Before the Texas Revolution and the annexation debates of the 1830s and 1840s, portions of Texas were briefly considered part of the United States, all stemming from the Louisiana Purchase. With the Louisiana Purchase in 1803, the United States doubled in size overnight. America had pushed far to the West into the wide expanses of the High Plains and to the frontiers of Texas. The French government was very evasive in what they considered to be the extent of the Louisiana Territory. The question of whether the United States owned any portion of Texas was ultimately put in the hands of one of America’s top diplomats, John Quincy Adams.
The French connection to Texas dated back into the 1600s. In 1682, French explorer Robert Cavalier, Seuer de la Salle, claimed the entire Mississippi River Valley and all of its tributaries for France. This, by default, included the Red River, stretching to include the entire modern Texas panhandle and the watershed in the counties all along the modern North Texas border with Oklahoma. It also came to include the French claim on the Sabine River and the lands of what is now most of East Texas and the failed colony in Matagorda Bay.
John Quincy Adams, born in 1767, was the son of John Adams, the nation’s second president and part of the committee that wrote the Declaration of Independence with Thomas Jefferson. Like his father, he was a skilled attorney and learned the art of diplomacy while his father served as the American ambassador to The Netherlands and later to Great Britain. In 1794, President George Washington appointed Adams as ambassador to The Netherlands, at only the age of 27. Two years later, Washington also named him to double as ambassador to Portugal. He would serve as ambassador to Prussia from 1797 until 1801 before returning to the United States. He became the U. S. Senator from Massachusetts in 1803.
Not long after Adams arrived in Washington, DC, Congress learned about the treaty with France purchasing Louisiana. France had turned the entire area over to Spain after the end of the French and Indian War in 1763. Forty years later, with Spain under control of French leader Napoleon Bonaparte, Spain was forced to give the land back to France. Uncertain what to do with the territory and needing money to finance his wars, Napoleon had his ministers sell the territory to an eager United States for $15 million (or about $335 million in 2019 dollars). There was brief debate over what territory was included with Louisiana, whether France was the rightful owner of the territory, and whether the federal government had the authority to even purchase the land. Seeing the overwhelming opportunity, the United States Senate, including Adams, voted to approve the treaty by a vote of 26-6.
Adams had become Secretary of State under President James Monroe in 1817. By 1818, the United States faced a Spain that had regained its independence but was a rapidly weakening power. Spain faced rebellion in its colonies from Argentina to Mexico. Spain was unable to control Florida, and raids by the Seminoles into the United States had become a contentious issue. Spanish control in the area included the entire modern state of Florida, but the areas of the Alabama and Mississippi panhandles and the far eastern reaches of Louisiana east of the Mississippi River and north of Lake Pontchartrain had been seized by American settlers in 1810 even though Spain still had legal ownership. Adams entered into negotiations with Spanish Ambassador Luis de Onis to purchase Florida. Spain had rejected earlier offers, but with Spain facing a collapsing position in the Americas and the threat of American military power, Onis reluctantly gave in.
Onis, however, was not willing to give up everything in exchange for nothing. As negotiations continued, Onis pressed for clear border between the U. S. and Spain, a request that Adams was willing to support. As American claims on East Texas were shaky at best, Adams gave ground on claims into the Sabine and Red River Valleys. The Adams-Onis Treaty would acquire East Florida and also set a western border at the Sabine River to the Thirty-Second Parallel and North to the Red River. The border would then run along the Red River to the One-Hundredth Meridian to the Arkansas River and then to the Rocky Mountains and to the Pacific Ocean. The treaty was signed on February 22, 1819.
The treaty was approved by the Senate though there were many expansionists upset by what they saw as the “giveaway” of Texas. When the subject of annexing the independent Texas arose in the 1830s and 1840s, many supporters loudly called for the “re-annexation” of Texas. The treaty nevertheless gained Florida for the Union and gave East and North Texas its modern boundary. It also gave America a solid claim on the Pacific Ocean as a boundary. Texas would later be admitted, becoming the 28th state admitted into the Union on December 28, 1845.