Rios v. Davis 373 S.W. 2d 386 (Tex. Ct. Civ. App. 1963) Rios and Davis were in a car accident. Rios sued for $17k for personal injuries. Rios argued that his injuries were proximately caused by Davis' negligence. Davis argued that Rios was barred from recovery because of contributory negligence. Turns out, Davis had already been sued by the Popular Dry Goods company, who owned a truck that was also involved in the same accident. In that case, Davis claimed that Popular was contributorily negligent, and sued Rios for damage to his car. The Trial Court found Rios and Popular both guilty of negligence and both were the proximate cause of the accident. The Trial Court also found that Davis was also guilty of negligence and was a proximate cause of the accident. Popular was barred from recovery against Davis, and Davis was barred from recovery against Rios. Under the contributory negligence doctrine, if you are somehow partially responsible for an accident, you can't recover for damages even if other people are also partially responsible. The Trial Court found for Davis, Rios appealed. The Trial Court agreed that Rios was already found to be contributorily negligent at the first trial, and was therefore barred by collateral estoppel and res judicata from bringing up the issue again at this new trial. The Appellate Court reversed and remanded for trial. The Appellate Court found that the sole basis for ruling in the first case had to do with Davis's negligence. The finding that Rios was also negligent was not "essential or material to the judgment in that case." The initial case turned on Davis and Popular being contributorily negligent. Once the court found that they were contributorily negligent, they were barred from recovery against Rios, regardless of whether Rios was also negligent. Since Rios had come out a winner in the initial case, he had no reason to present evidence that he was not negligent. Also, since Rios had come out the winner, he was legally precluded from appealing the fact that he had been found negligent. Basically, the idea is that if there is an issue that is central to a case, then both sides have a good reason to present the best evidence they can in their own defense. However, when an issue isn't really important to a case, the parties may not bother to present a strong defense against that issue. Therefore, the only issues that are precluded from being brought up in a second case due to issue preclusion (aka estoppel by judgment) are those that were absolutely essential to the judgment in the initial case. In addition, if you win a case, you can't appeal. So if the judge finds for the other party on a specific issue, but you win the case overall, you never received due process on that issue, so it can still be raised in a subsequent case.