In this way, Mr. Obama seemed to signal a new paradigm for black-white discussion — one in which a public figure could use language outside the defined limits of acceptability and expect to be judged in some larger context. In other words, the promise of Mr. Obama’s candidacy wasn’t a post-racial society where no one was going to notice the color of your skin; it was a society where you could talk about race — no matter what color you were — without automatically being called a racist.