(1) In federal habeas proceedings when violations of Brady v. Maryland, 373 U.S. 83, 83 S. Ct. 1194, 10 L. Ed. 2d 215 (1963), Giglio v. United States, 405 U.S. 150, 154, 92 S. Ct. 763, 31 L. Ed. 2d 104 (1972) and Napue v. Illinois, 360 U.S. 264, 271, 79 S. Ct. 1173, 3 L. Ed. 2d 1217 (1959) are found is the effect of multiple violations to be addressed cumulatively or may an appeals court ignore the cumulative effects and concentrate on a single violation?

(2) When a criminal defendant shows multiple violations of the above must a habeas petitioner show an acquittal to merit a new trial?

(3) When the government fails to prove essential conduct elements of all convicted counts at trial does this affect the court's materiality analysis in the context of the above violations?

(4) Is the government in a criminal trial required to provide impeachment evidence relating to a cooperating witnesses' criminal history that is in their possession?

Whether the cumulative effect of Brady, Giglio, and Napue violations must be considered or if an appeals court can ignore the cumulative effects and concentrate on a single violation