<P> Filibusters like William Walker continued to garner headlines in the late 1850s, but to little effect . Expansionism was among the various issues that played a role in the coming of the war . With the divisive question of the expansion of slavery, Northerners and Southerners, in effect, were coming to define manifest destiny in different ways, undermining nationalism as a unifying force . According to Frederick Merk, "The doctrine of Manifest Destiny, which in the 1840s had seemed Heaven - sent, proved to have been a bomb wrapped up in idealism ." </P> <P> The Homestead Act of 1862 encouraged 600,000 families to settle the West by giving them land (usually 160 acres) almost free . They had to live on and improve the land for five years . Before the Civil War, Southern leaders opposed the Homestead Acts because they feared it would lead to more free states and free territories . After the mass resignation of Southern senators and representatives at the beginning of the war, Congress was subsequently able to pass the Homestead Act . </P> <P> Manifest destiny had serious consequences for Native Americans, since continental expansion implicitly meant the occupation and annexation of Native American land, sometimes to expand slavery . This ultimately led to confrontations and wars with several groups of native peoples via Indian removal . The United States continued the European practice of recognizing only limited land rights of indigenous peoples . In a policy formulated largely by Henry Knox, Secretary of War in the Washington Administration, the U.S. government sought to expand into the west through the purchase of Native American land in treaties . Only the Federal Government could purchase Indian lands and this was done through treaties with tribal leaders . Whether a tribe actually had a decision - making structure capable of making a treaty was a controversial issue . The national policy was for the Indians to join American society and become "civilized", which meant no more wars with neighboring tribes or raids on white settlers or travelers, and a shift from hunting to farming and ranching . Advocates of civilization programs believed that the process of settling native tribes would greatly reduce the amount of land needed by the Native Americans, making more land available for homesteading by white Americans . Thomas Jefferson believed that while American Indians were the intellectual equals of whites, they had to live like the whites or inevitably be pushed aside by them . Jefferson's belief, rooted in Enlightenment thinking, that whites and Native Americans would merge to create a single nation did not last his lifetime, and he began to believe that the natives should emigrate across the Mississippi River and maintain a separate society, an idea made possible by the Louisiana Purchase of 1803 . </P> <P> In the age of manifest destiny, this idea, which came to be known as "Indian removal", gained ground . Humanitarian advocates of removal believed that American Indians would be better off moving away from whites . As historian Reginald Horsman argued in his influential study Race and Manifest Destiny, racial rhetoric increased during the era of manifest destiny . Americans increasingly believed that Native American ways of life would "fade away" as the United States expanded . As an example, this idea was reflected in the work of one of America's first great historians, Francis Parkman, whose landmark book The Conspiracy of Pontiac was published in 1851 . Parkman wrote that after the British conquest of Canada in 1760, Indians were "destined to melt and vanish before the advancing waves of Anglo - American power, which now rolled westward unchecked and unopposed". Parkman emphasized that the collapse of Indian power in the late 18th century had been swift and was a past event . </P>

What did nineteenth-century american expansionists mean by the term manifest destiny