Supreme Court of the United States (a.k.a. "the law of the land")
1984 California v. Trombetta
But criminal defendants are entitled to much more than protection against perjury. A defendant has a constitutionally protected privilege to request and obtain from the prosecution evidence that is either material to the guilt of the defendant or relevant to the punishment to be imposed. Brady v. Maryland, 373 U.S., at 87. Even in the absence of a specific request, the prosecution has a constitutional duty to turn over exculpatory evidence that would raise a reasonable doubt about the defendant's guilt. United States v. Agurs, 427 U.S., at 112.
"Jeff, Jeff Dusek? Please pick up the white courtesy phone."
Well, now we know how to get around that one: make it a point not to find any no matter how obvious it may be.