How important was the westward movement in relation to major social and political developments?

One major political development of westward expansion happened during the early days of the history of the United States. The Northwest Ordinance of 1787 created a system where new territories could become states. Without this, the western lands might have been treated like colonies and they would have split away from the United States. Another great political development was that women received the right to vote in many western territories before the Nineteenth Amendment was ratified in 1920. Wyoming was the first state to allow women to vote in 1869. Due to a shortage of eligible voters, women were needed on voter rolls in order to achieve a quorum in many outlying areas. The increasing number of westward settlers also spurred the United States to grow, and the Oregon Trail forced the United States and Britain to come to terms over who owned the Oregon Territory.
Socially, while Native Americans did not fare well in westward expansion, African Americans usually received better treatment in the West than in the South and East. Many African Americans left the South after the Civil War and traveled to the new territories in order to make their fortunes. Many found success and fame as cowboys as the open range was quite egalitarian and one was valued for one's abilities over one's race.