A federal judge is making headlines by declaring that the National Security Agency's bulk collection of millions of Americans' telephone records is likely unconstitutional. But even he realizes his won't be the last word on the issue.

U.S. District Court Judge Richard Leon put his decision to grant an injunction against the NSA on ice Monday, predicting a government appeal would take at least six months. Even after a federal appeals court rules, the Supreme Court probably will have the last word.

Stephen Vladeck, a national security law expert at the American University law school, called Leon's ruling the "opening salvo in a very long story."

In his ruling, Leon granted a against the collecting of the phone records of two men who had challenged the program.