DIANE P. WOOD, Circuit Judge.

Plaintiffs Kathy Carver and Fred Kient-zle work as deputy sheriffs for the Adams County, Illinois, Sheriffs Department. Each of them was suspended without pay for a brief period of time. Those suspensions led their union to file a grievance on their behalf before the Illinois State Labor Relations Board (“ISLRB”), claiming that they had been suspended in retaliation for their union activities. That proceeding was ultimately settled. Eight months before the settlement, Carver and Kientzle filed the present suit under 42 U.S.C. § 1983, claiming that the way their suspensions were handled violated their constitutional rights to procedural due process. The district court dismissed the case, believing that the proceedings before the ISLRB were res judicata for the § 1983 case. We disagree for several reasons and remand the case for further consideration.

Sheriff Robert Nall and Chief Deputy Jon McCoy suspended Carver for ten days without pay on May 6, 1996. They suspended Kientzle for three days without pay at the same time. Neither plaintiff received a pre-suspension hearing, nor was either given an opportunity to respond to the allegations made against him or her. In addition, even though both Carver and Kientzle asked for a post-suspension hearing before the Adams County Merit Commission, neither was granted one.

Their union, believing the suspensions were in retaliation for Carver’s and Kient-zle’s union activities, filed the unfair labor practice charges against Sheriff Nall with the ISLRB. That led to a settlement on March 25, 1997. The settlement agreement provided that Carver’s suspension would be reduced to three days and Kient-zle’s would be expunged, and each plaintiff would receive back pay for the entire duration of the original suspension. It also stated that the union would withdraw its charges against Sheriff Nall. Most importantly for present purposes, it finally stated that “Deputies Kientzle and Carver hereby expressly waive any and all other claims for said backpay arising from these disciplinary actions.”

Some eight months before the settlement agreement was signed, on July 26, 1996, Carver and Kientzle had filed the present action alleging due process viola *515 tions in their treatment. Their second amended complaint requested back pay and an injunction against the Sheriffs Department that would prohibit it from imposing suspensions without hearings. The suit named Sheriff Nall, Chief Deputy McCoy, and five members of the Adams County Merit Commission as defendants. After the March 25, 1997, settlement was signed, the defendants moved for judgment on the pleadings, arguing that the § 1983 action was now barred by res judi-cata. The district court agreed and dismissed the action.

The Supreme Court has held that the preclusive effect of a state court judgment in a later federal court action must be determined using the principles of the full faith and credit statute, 28 U.S.C. § 1738. See Matsushita Elec. Indus. Co. v. Epstein, 516 U.S. 367, 373, 116 S.Ct. 873, 134 L.Ed.2d 6 (1996); Marrese v. American Acad. of Orthopaedic Surgeons, 470 U.S. 373, 380, 105 S.Ct. 1327, 84 L.Ed.2d 274 (1985). Here, of course, we are met with the initial obstacle that there is neither a state court judgment nor even a state administrative agency’s formal resolution of the matter, so there is no underlying state decision of any kind that might preclude the federal suit. Furthermore, to the extent that it is tangentially relevant, we note that our decision in Majeske v. Fraternal Order of Police, Local Lodge No. 7, 94 F.3d 307 (7th Cir.1996), does not stand for the proposition that res judicata effects can spring from settlements. Ma-jeske held only that the fact that a court judgment may have had its roots in a settlement (and thus be a consent decree), rather than in full-blown litigation, makes no difference for the application of § 1738. But the fundamental point remains that res judicata cannot operate in the absence of a judgment. A settlement agreement that has not been integrated into a consent decree is not a judgment and cannot trigger res judicata.

Open and shut as this point is, for some reason it is not the ground that Carver and Kientzle argued in their opening brief on appeal. Ordinarily, this would mean that they have waived this ground for relief. In this case, however, the ap-pellees specifically addressed the § 1738 point in their responsive brief. They have thus waived the chance to argue that Carver and Kientzle forfeited this argument, and we regard the point as fairly before us. The appellees suggest that even though the ISLRB decision is not entitled to full faith and credit, it still has preclu-sive effects under the federal common law of claim preclusion, citing University of Tennessee v. Elliott, 478 U.S. 788, 106 S.Ct. 3220, 92 L.Ed.2d 635 (1986). But the Elliott Court did no more than recognize that traditional, federal common law principles of preclusion apply to state administrative actions in § 1983 cases. Id. at 797, 106 S.Ct. 3220. It directed federal courts to give state administrative factfinding the same preclusive effect it would have in state courts. Id. at 799, 106 S.Ct. 3220.

In our case, unlike in Elliott, the administrative ease before the ISLRB was settled, the charges were withdrawn, and the ISLRB never took any action. No preclusion doctrines, statutory or common law, operate in the absence of an underlying judgment or administrative finding. Illinois, like every other jurisdiction of which we are aware, requires at a minimum an administrative determination before it will apply preclusion doctrines. E.g., Marco v. Doherty, 276 Ill.App.3d 121, 212 Ill.Dec. 820, 657 N.E.2d 1165, 1168 (1995); Godare v. Sterling Steel Casting Co., 103 Ill.App.3d 46, 58 Ill.Dec. 588, 430 N.E.2d 620, 623 (1981). The absence of any such determination here from the ISLRB means that there is no preclusion under Elliott either.

The general inapplicability of claim preclusion in the present situation makes it unnecessary for us to discuss in detail the other reasons for reversal Carver and Kientzle have presented on appeal. They have argued that preclusion should not *516 apply because (1) the ISLRB lacked jurisdiction to adjudicate a due process violation, (2) the ISLRB could not award the full measure of relief they sought, and (3) there was no identity of causes of action between the labor violation before the ISLRB and the due process claim before the district court. The first of these is also sufficient reason to reverse the district court’s judgment. This court has held that, where a plaintiff has a set of claims arising from one series of events, and where she has an unconstrained choice to proceed in a forum with jurisdiction to hear all her claims or a forum with limited jurisdiction, if she chooses to proceed in the latter, the claims that fall outside its jurisdictional reach will be barred. Waid v. Merrill Area Pub. Sch., 91 F.3d 857, 864-65 (7th Cir.1996). Here, however, Carver and Kientzle had no such unconstrained choice. On the one hand, the ISLRB has exclusive jurisdiction to hear unfair labor practice grievances of Illinois state employees. See Stahulak v. City of Chicago, 291 Ill.App.3d 824, 225 Ill.Dec. 916, 684 N.E.2d 907, 911 (1997); Foley v. AFSCME Council 31, Local 2258, 199 Ill.App.3d 6, 144 Ill.Dec. 903, 556 N.E.2d 581, 583-84 (1990). On the other hand, the ISLRB is not empowered to hear a civil rights claim. Thus, because the federal court could not hear the unfair labor practice grievance and the state tribunal could not hear the civil rights claim, Carver and Kientzle were forced to split their claims as they did. Claim preclusion does not operate so harshly as to bar whichever set of claims the chosen forum could not hear. Waid, 91 F.3d at 865, discussing Restatement (Second) of Judgments § 26 cmt. c.

Although we are reversing the district court’s decision to dismiss the case on res judicata grounds, we wish to emphasize that this ruling does not mean that the settlement agreement was a nullity. On remand, it will be open to the parties to debate the effect of the contractual release contained in the agreement on Carver’s and Kientzle’s § 1983 suit. Because this has not been explored in the proper context, we offer no further opinion on it at this time.

The judgment of the district court is Reversed and the case is Remanded for further proceedings consistent with this opinion.