The federal Supreme Court can invalidate a state law, only if it finds some basis in federal law for doing so. Associate Justice William Douglas's majority opinion in Griswold was based on the U.S. Constitution. But how could he do that? The Constitution says nothing about contraception.
Douglas wrote that such a ban violates a married couple's privacy. But the Constitution also says nothing about a right to privacy.
Douglas wrote that "specific guarantees in the Bill of Rights have penumbras, formed by emanations from those guarantees that help give them life and substance." He cited amendments #1, 3, 4, 5, 9 and 14, and argued that those provisions, considered in combination with each other, establish a right to privacy.
In dissent, Associate Justice Hugo Black rejected Douglas's analysis:
The Court talks about a constitutional "right of privacy" as though there is some constitutional provision or provisions forbidding any law ever to be passed which might abridge the "privacy" of individuals. But there is not.
But Black was one of only two justices (the other was Potter Stewart) dissenting on the nine-member Court, so the state law went into the wastebasket.
So what?, one might ask. Even though the largest religious denomination in this country still (ineffectively) forbids contraception, the view that it should be allowed is not particularly controversial among the general public.
But the principle of stare decisis is not limited to providing that a precedent applies to future cases with the same facts as the original. No two cases present exactly the same facts.
In subsequent years, the right of privacy that was established in Griswold, was applied to other issues involving sex and reproduction that are more controversial than married couples' use of contraception.