They DON'T??
We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.--
Except that - like it or not - the Constitution only authoritatively means why SCOTUS says it does. See post https://freerepublic.com/focus/news/4128785/posts?page=8#8