I'm sure most readers are familiar with the Latin term ad libitum. It means "at liberty" and indicates a free choice. In a jazz performance it means that the performer is playing phrases that are not written out, but are rather a creation of the moment based on the artist's tastes and preferences. In classical music it is used to indicate that a passage or part may be left out, or it may mean a passage may be repeated as many times as needed. The term is used in non-musical contexts as well, but generally means some kind of free choice.
In an 1825 letter to Edward Livingston, Thomas Jefferson used the same expression:
"This member of the Government [the court system] was at first considered as the most harmless and helpless of all its organs. But it has proved that the power of declaring what the law is, ad libitum, by sapping and mining slyly and without alarm the foundations of the Constitution, can do what open force would not dare to attempt."
This quote, and others on this site, show that Jefferson was very wary of the power that the courts might take upon themselves, over and above that which the Founders intended when they drafted the Constitution. How ironic then that the Supreme Court "gave new meaning" to the First Amendment (in the words of the American Civil Liberties Union) as they based several decisions on a metaphor Jefferson used in another letter: "separation of church and state." Giving new meaning to the First Amendment is not a role Jefferson envisioned for the courts.
Learn more from the University of Virginia site