It is often said that our Constitution is alive. As the Supreme Court reinterprets the law in different eras, our rights both grow and diminish—sometimes with glacial slowness, sometimes with breathtaking speed. In the past few years we have seen the full-blown emergence of a new constitutional right of enormous importance—an intensely personal right that may benefit many of us far more than our political freedoms of speech, press, and assembly. Though often called the right to privacy, it is better described with a phrase used by the Supreme Court in 1866, when it ruled that we all have…