Manifest Destiny: Key Advocates

During the mid-19th century, the concept of Manifest Destiny emerged as a powerful ideology in the United States. This belief held that Americans were destined to expand across the continent, bringing with them their culture and institutions. This notion fueled significant territorial acquisition, including the annexation of Texas and the Oregon Trail's migration. However, involvement in foreign lands also raised ethical questions regarding the treatment of indigenous populations and the legality of acquiring new territories. Based on this context, which of the following leaders most vigorously advocated for expansionism during the period of Manifest Destiny?