Who put the separate-but-equal doctrine in place?

In the United States, the "separate but equal" doctrine refers to legally sanctioned segregation arising (in part) from the US Supreme Court decision in Plessy v. Ferguson, (1896).

"Separate but equal" allowed states to pass laws requiring separate accommodations and facilities for people on the basis of race or color in order to prevent African-Americans, who had recently been freed from slavery, from intermingling with whites, who believed themselves superior to African-Americans.

The Court followed several lines of reasoning that allowed segregation, and its racist Jim Crow laws, to flourish: 1) The Fourteenth Amendment didn't apply to private individuals or businesses, only to government entities; 2) The Fourteenth Amendment wasn't intended to prevent states from enacting "reasonable" laws that segregated individuals by race "for the public good"; 3) If the accommodations were equal (which was rarely the case), there was no violation of the Fourteenth Amendment.

White Americans used the "separate but equal" doctrine to maintain dominance over African-Americans and to limit their interaction with them as peers. Since African-Americans had little social or political power at the time, they were forced to comply with unconstitutional, racist laws and discriminatory treatment that has yet to be completely overcome.

Amendment XIV, Section I

All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the state wherein they reside. No state shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any state deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.