Which decision is indicative of how the Supreme Court interpreted the Fourteenth Amendment and state discretion in civil rights matters in the decades after the Civil War?

Plessy v. Ferguson

Explanation:

Plessy v. Ferguson was a landmark ruling of the United States Supreme Court  in 1896 that provided legal justification for segregation and upheld the constitutionality of racial segregation laws on buses, public facilities etc.

This case came as a result of an incident in which an African American train passeger Homer Plessy refused to sit in the black only section of the train. Plessy argue that segregation law violate the Equal Proctection Clause of th Fourteenth Amendment which forbids states from denying any person within their jurisdiction the equal protection of the laws. However Ferguson ruled that separate but equal facilities were constitutional.

Ferguson stand came to be known as separate but equal doctrine

Supreme Court Of The United States. U.S. Reports: Plessy v. Ferguson, 163 U.S. 537 . 1895.

it is a part of john locke's natural rights popular during the age of enlightenment that people had inalienable rights to life, liberty and property. this was reflected by thomas jefferson in his declaration of independence as rights to life,liberty and the pursuit of happiness.

another line in the declaration of independence is that people have certain rights just because they are human. humans are capable of obeying the three natural rights john locke mentioned making them governable by these laws and therefore entitled to these rights as well.