3. Principles of res judicata, which prohibit the splitting of a cause of action into two or more lawsuits, may create incentives for the joinder of related claims even in the absence of a rule of compulsory joinder. See Blume, Required Joinder of Claims, 45 Mich. L. Rev. 797

(1947). Thus, for example, if A and B are involved in an automobile accident in which A suffers both bodily injury and damage to her automobile, the risk of res judicata may lead A to join both claims in one action, even though Federal Rule 18 does not require her to do so.

We take up the topic of preclusion in Chapter 17.