“The essence of the defense of res judicata is that the same parties may not litigate a second suit on the same cause of action. As a general rule, a final valid judgment on the merits in favor of or against a litigant is a complete bar to further litigation on the same cause of action or defense between or among the same parties. Res judicata is now frequently called claim preclusion, arising when a second suit involves “(1) the same cause of action (2) between the same parties (3) after a final judgment on the merits in the first suit.””
[California Affirmative Defenses [certain citations omitted]]
