XVIII. Defenses: Contributory and Comparative Fault

As with intentional tort, negligence doctrine allows for some defenses. These often focus on the behavior of the plaintiff-victim rather than defendant-wrongdoer. In its more traditional form, to validate a defense was to extinguish all liability: defenses of merit would be complete ones.

Contributory negligence folds in all the elements of a negligence case — but this time evaluating the plaintiff’s rather than the defendant’s behavior, with the plaintiff as his or her own victim. Traditionally, any amount of negligence by the plaintiff extinguished their case against the defendant. The harshness of that rule led to some countervailing exceptions to flip the “all” of the defense back to “nothing” — exceptions like the last clear chance doctrine, by which the plaintiff’s negligence wouldn’t count against the case if the plaintiff’s poor behavior had made the plaintiff helpless, and then the defendant, seeing that, acted negligently anyway.

Starting in the 1960’s and 70’s, American tort law started to split the difference between all or nothing. The concept of comparative negligence was introduced, and through it juries might be asked to compare the defendant’s negligence against the plaintiff’s, deducting the plaintiff’s share of responsibility for their own harm from any recovery against a defendant whose behavior also contributed to the harm. How to make such comparisons is far from clear, especially in cases with multiple defendants, each playing very different roles.