The equal protection standard of the constitution has one clear and central meaning - it absolutely prohibits invidious [repugnant] discrimination by government...Under our Constitution, any official action that treats a person differently on account of his race or ethnic origin is inherently [by nature] suspect and presumptively [probably] invalid...Under the Constitution we have, one practice in which government may never engage in the practice of racism - not even "temporarily" and not even as an "experiment."