Penumbra (law)

[12] The definition of the term was originally derived from its primary scientific meaning, which is "a space of partial illumination (as in an eclipse) between the perfect shadow on all sides and the full light".

[14] Brannon P. Denning and Glenn H. Reynolds have described this interpretive framework as the process of "drawing logical inferences by looking at relevant parts of the Constitution as a whole and their relationship to one another.

"[15] Glenn H. Reynolds has also characterized penumbral reasoning as a process of "reasoning-by-interpolation" where judges identify the full scope and extent of constitutional rights.

[19] Second Circuit Court of Appeals Judge Learned Hand also used the term eleven times between 1915 and 1950, usually to place emphasis on words or concepts that were ambiguous.

[24] Likewise, in Olmstead v. United States, Justice Holmes argued that evidence obtained through wire-tapping should not be admitted at trial, and that "the penumbra of the Fourth and Fifth Amendments covers the defendant".

[28] When arguing that a group of legislators lacked standing, he wrote, "[n]o doubt the bounds of such legal interest have a penumbra which gives some freedom in judging fulfillment of our jurisdictional requirements".

[29] J. Christopher Rideout and Burr Henly note that the term achieved prominence after Justice Douglas' majority opinion in Griswold v. Connecticut held that a right to privacy existed in the penumbra of the constitution.

The Fourth Amendment explicitly affirms the "right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures."

[43] District of Columbia Circuit Judge Robert Bork, for example, was a particularly vocal critic of Supreme Court rulings that identified rights that are not explicitly enumerated in the text of the constitution.

[47] Robert J. Pushaw Jr. also described penumbral reasoning as a "transparently fictional" process,[48] and Jennifer Fahnestock has cautioned that "implicit constitutional rights" are vulnerable to being lost "due to their lack of permanency".