Why would the us government have forced the cherokee to give up their land land move west?

In 1838 and 1839In his 1942 painting Cherokee Trail of Tears, Robert Lindneux depicts the forced journey of the Cherokees in 1838 to present-day Oklahoma.Cherokee Trail of Tears U.S. troops, prompted by the state of Georgia, expelled the Cherokee Indians from their ancestral homeland in the Southeast and removed them to the Indian Territory in what is now Oklahoma. The removal of the Cherokees was a product of the demand for arable land during the rampant growth of cotton agriculture in the Southeast, the discovery of gold on Cherokee land, and the racial prejudice that many white southerners harbored toward American Indians.
I tried explaining the best I could, hopefully it helped!! :)

A. southerners underestimated republicans eagerness to end slavery.