What was the main argument in plessy v Ferguson apex?

The main argument in Plessy v. Ferguson (1896) centered around the constitutionality of racial segregation laws. Homer Plessy, who was of mixed race, challenged Louisiana's Separate Car Act, arguing that it violated the Equal Protection Clause of the Fourteenth Amendment. The Supreme Court upheld the segregation law, establishing the "separate but equal" doctrine, which justified racial segregation as long as the separate facilities were considered equal, thereby reinforcing systemic racism and discrimination in the United States.