How did United States change socially between 1776 and 1870?

The United States change socially between 1776 and 1870 when declared the 13th ammendment that abolished the slavery. That there will be neither slavery nor involuntary serviture except as a punishment for crime whereof the party shall have been duly convicted. Then the 14th ammendment declared which defined a citizen as any person born or naturalized in the US. This addresses citizenship rights and equal protection of the laws and was porposed in the response to issues related to fromer slaves following the Americal Civil War. Then lastly, the 15th amendments that prohibits denying the right to vote to someone because of their race. These 3 amendments apparently change the United States change socially.

Abolished slavery and gave black men citizenship rights.

The Constitution did not address the issue of slavery and therefore left the issue to be dealt within the first 100 years. Slavery in the US increased in number and influence during the early part of the 19th century. As the laws strengthen against blacks, the abolitionist movement also rose and gained strength. This culminated with the Civil War and the passage of the 13th Amendment in 1865 ending slavery and the 14th Amendment in 1868 which gave blacks citizenship rights. In 1870, the last of the Civil War Amendments were passed (15th Amendment) giving black men the right to vote.