The supreme court’s plessy v. ferguson decision ruled that louisiana’s separate car act promoted unconstitutional segregation. maintain public peace and good order. did not constitute segregation. was required under the fourteenth amendment.

The correct answer is: "helped maintain public peace and good order".

The "separate but equal" lemma that was accepted in the decision enacted by the US Supreme Court in 1896 in the Plessy v. Ferguson case. Such decision allowed the proliferation of segregated public facilities under the belief that, if facilities were equal in quality (for example, schools or public transport), such system was not violating the equality of rights provision that had been guaranteed for all US citizens in the 14th Amendment to the US Constitution.

Moreover, the decision stated that the existence facilities shared only by people of the same race would avoid tensions and public order would be better preserved.

d.he wanted to send diplomats to communist countries.