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.”