When Does May Mean Must?

INTRODUCTION

In any reasonable civil procedure world, there ought to be a close relationship between the parties’ right to join claims in their first lawsuit and the scope of res judicata in subsequent suits between them. If, for example, the rules of joinder did not allow plaintiffs to join counts for property damage and personal injury in a single lawsuit, it would be a rigid system indeed that barred an accident plaintiff who had sued for damage to his car in one suit from bringing a separate action to recover for his personal injuries in the accident. Similarly, if the joinder rules limited a plaintiff to proceeding on a single theory, such as negligence, in his first suit, it would be unfair to bar him from starting a second action on a strict liability theory. One way or another, the system ought to offer parties a chance to have all of their claims heard, either through limited claims in multiple suits or multiple claims in a single suit.

The early English common law followed the first course, allowing multiple actions on different theories or seeking different relief. Under the common law system, the rigid limitations on joinder of claims frequently prevented plaintiffs from seeking full relief in a single action. For example, a plaintiff who sued at law for damages for trespass could not get an injunction against further trespasses in the same suit; he had to go to an equity court for that. Because the plaintiff was forced by these limitations to split his cause of action, the preclusion rules did not bar him from bringing the second action even though it arose out of the same occurrence as the first.

The federal courts (and many state systems as well) have chosen the second course, allowing many claims to be heard in a single action. This approach is implemented by extremely broad rules governing pleading and joinder. See Rules 8(a)(3), 8(d)(3), 13, 14, 18, 20. Under these liberal joinder rules, plaintiffs have broad power to join all their theories of recovery in their initial suit. Consequently, they will seldom be able to argue that they should be allowed to start a new action based on the same occurrence because they were unable to assert an omitted claim in the first suit.

For example, Fed. R. Civ. P. 18(a) allows the plaintiff to join virtually all possible theories of recovery in a single action. It is hardly unreasonable therefore to hold that res judicata bars him from suing later on any theory that is omitted from the first suit. In this situation the may of the rules clearly means must when the effects of res judicata are considered. If Elbers sues Doe Chemical Company for negligently manufacturing a drug, Rule 18(a) allows but does not require him to assert a separate strict liability claim against Doe based on the same events. See also Fed. R. Civ. P. 8(d)(3) (authorizing alternative or inconsistent pleading). However, if Elbers leaves out the strict liability claim, res judicata will bar him from asserting it in a later action. This is simply another theory of recovery for the same injuries already sued upon, and any claims arising from that occurrence that are not joined in Elber’s first action will be barred by res judicata. See Chapter 26, example 2.