Question

Which of these ideas would supporters of the Plessy v. Ferguson ruling most likely have agreed with?
that “social rights” were a part of “civil rights”
that the Constitution should be interpreted without regard to race
that “separate but equal” was a valid legal doctrine
that "separate but equal" did not justify racial segregation

Answer 1

That “separate but equal” was a valid legal doctrine.

Supporters of Plessy v. Ferguson (1896) argued the Constitution allowed state-mandated racial segregation so long as segregated facilities were equal in quality.