Final answer:
James Long, a planter from Mississippi, led an unauthorized military expedition in 1819 across the Sabine River attempting to take control of Texas from Spain as a filibuster. Despite briefly capturing Nacogdoches, Long was later ousted by Spanish forces and ultimately killed upon his return in 1820.
Step-by-step explanation:
The filibuster accused of working with U.S. Army General Wilkinson to steal land away from Spain was James Long, a planter from Natchez, Mississippi. In the summer of 1819, Long became a filibuster, leading three hundred men on an expedition across the Sabine River with the intent to seize control of Texas. His efforts ended with the capture of Nacogdoches and the establishment of a brief republican government before being ousted by Spanish troops. Tragically, after a subsequent attempt in 1820, Long was arrested by Spanish authorities and killed.
The filibusters viewed Spain as an obstacle to the expansion of American slavery and territory. Their actions, driven by a belief in White racial superiority, reveal a period in American history where expansionist fervor and the pursuit of land for slavery were at odds with the established U.S. foreign policy. In essence, filibusters embodied the unsanctioned and aggressive pursuit of American imperialism and the expansion of an American empire of slavery.