According to justice brown’s opinion in plessy v. ferguson, what did he consider segregation to be?

Segregation was not inherently a violation of the Fourteenth Amendment because it did not deny services or citizenship rights.

Justice Brown stated segregation is not a violation of the Fourteenth Amendment (which grants citizenship rights) if the facilities are equal. By providing equal access to Constitutional rights even if in segregated facilities, the segregation is allowed. If the laws state for unequal treatment then segregation would be in violation of the Fourteenth Amendment.

necessary and proper clause. the congress shall have power to all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states, or in any department or officer thereof.

because it took place after the war of 1812 had come to an end.