The Virginia Business Litigation Blog
“Res judicata” is Latin for “the thing has been judged.” It basically means that once you sue someone and obtain a result–win or lose–the matter is over and you can’t sue the same person again for the same harm. It’s like the civil equivalent of double jeopardy. The doctrine is designed to conserve judicial resources, deter multiple lawsuits, and promote reliance on judicial decisions. A party claiming that a suit is barred by res judicata must establish: (1) a previous final judgment on the merits; (2) an identity of the cause of action in both suits; and (3) an identity of parties or their privies in the two suits.
A recent example is provided by Nathan v. Takeda, in which the United States Court of Appeals for the Fourth Circuit affirmed the district court’s dismissal of a defamation claim based on res judicata grounds.
In an earlier case, Noah Nathan sued his employer, Takeda Pharmaceuticals America, for discrimination and retaliation under Title VII. After proceeding to judgment in that case, he filed a second suit, this time including several Takeda employees as defendants and changing his legal theory to defamation, conspiracy, and negligent supervision and retention. Nathan admitted the existence of a prior final judgment on the merits, but argued that his second case should have been allowed to proceed because the causes of action were different and different parties were involved.
Identity of the cause of action exists if two claims arise out of the same transaction or series of transactions or the same core of operative facts. The district court found that the factual allegations set forth in Nathan’s second lawsuit were “identical” to 
those in the first lawsuit, and therefore concluded that the causes of action were identical for res judicata purposes. The Fourth Circuit agreed, noting that the alleged wrongdoing in both cases arose from Takeda’s response to Nathan’s alleged performance difficulties in 2009. In the Title VII action, Nathan asserted that Takeda’s actions were discriminatory and retaliatory whereas in the defamation case, he alleged that the same actions constituted a conspiracy to defame him. Regardless of the change in legal theory, the claims clearly arose out of the same transaction or core of operative facts.
The test for whether two parties are in “privity” for purposes of res judicata is whether a party’s interest is so identical with another that representation by one party is representation of the other’s legal right. The district court found that the defendants in the defamation case were in privity with Takeda, the Title VII defendant, because they were Takeda employees and were acting as such at all relevant times. Again, the Fourth Circuit agreed, and found that res judicata barred Nathan from bringing a second suit. Any defamation claim he might have had should have been asserted in the first action.