Manifest Destiny is the 19th-century doctrine that advocated for the expansion of the United States across the North American continent. It was driven by the belief that Americans were divinely ordained to spread democracy and capitalism. This ideology justified westward expansion and led to significant events such as the annexation of Texas, the Oregon Trail, and the Mexican-American War. Manifest Destiny significantly influenced American identity and policy, often at the expense of Native American populations and other nations, raising debates about nationalism, imperialism, and morality in expansion efforts.