Turner's main point in his thesis was that the frontier played the most significant part in American History and that majority of history took place around the colonization of the West.
His arguments are considered innacurate because what mostly dominates American History are the Civil War, industrialization, slavery and immigration. He also ignores the existance of native americans who lived out of the settled area.
Because Jackson believed that the expansion to the west represented the American character characterized by: optimism, simplicity, opportunity and rebirth. This was written in an essay entitled The Significance of The American Frontier in American History by the historian Fredrick Jackson Turner in 1893.
The North favored the admission of California to the union. The Compromise of 1850 admitted California as a free territory but also allowed for the Fugitive Slave, which allowed for the recapture of fugitive slaves anywhere in the United States.
