In United States v. Armstrong, 517 U.S. 456, 134 L. Ed. 2d 687, 116 S. Ct. 1480 (1996), the United States Supreme Court rejected the notion that selective prosecution qualifies as an affirmative defense. The Armstrong Court stated: "A selective-prosecution claim is not a defense on the merits to the criminal charge itself, but an independent assertion that the prosecutor has brought the charge for reasons forbidden by the Constitution. Armstrong, 517 U.S. at 463, 134 L. Ed. 2d at 698, 116 S. Ct. at 1486. In Armstrong, the court determined that a defendant must satisfy demanding standards before discovery on the issue of selective prosecution is proper by stating: "Our cases delineating the necessary elements to prove a claim of selective prosecution have taken great pains to explain that the standard is a demanding one. These cases afford a 'background presumption' [citation] that the showing necessary to obtain discovery should itself be a significant barrier to the litigation of insubstantial claims. Armstrong, 517 U.S. at 463-64, 134 L. Ed. 2d at 698, 116 S. Ct. at 1486. The "background presumption" noted by the Court in Armstrong refers to the principle that most prosecutors act properly when carrying out their duties as an officer of the court. Armstrong, 517 U.S. at 464, 134 L. Ed. 2d at 698, 116 S. Ct. at 1486. This background presumption is very consistent with Illinois case law.