Is a final judgment on the merits of the case bars further claims by parties based on the same cause of action?

Under the doctrine of res judicata, a final judgment on the merits of the case bars further claims by parties based on the same cause of action. Montana v. United States, 440 U.S. 147, 153 (1979). Generally, the dismissal on the grounds of frivolousness pursuant to 28 U.C.S. Sec. 1915(d) is not a dismissal on the merits, but rather an exercise of the court's discretion under the in forma pauperis statute. Hernandez v. Denton, 112 S.Ct. 1728, 1734 (1992). "It could however, have a res judicata effect on frivolousness determinations for future in forma pauperis petitions." Id.