Intervening cause

An intervening cause is a later event that happens after a defendant's negligent act but before the injury, and it may break the chain of causation in tort law. In Intro to Law and Legal Process, it shows up when you decide whether the defendant should still be liable.

What is intervening cause?

An intervening cause is a new event that happens after the defendant’s initial negligent act and before the plaintiff’s injury, and it may change who is legally responsible for the harm. In Intro to Law and Legal Process, you use it when you trace causation in a tort claim and ask whether the original defendant should still be on the hook.

The basic idea is simple: someone acts carelessly, then something else happens, and that later event contributes to or causes the final injury. The legal question is whether that later event is enough to break the chain between the first act and the harm. If it is, the defendant may avoid liability, even though their conduct started the sequence.

Foreseeability matters a lot here. If the later event was something the defendant should have expected, courts may treat the chain of causation as still intact. For example, if a business leaves a hazard in a public area and a predictable crowd reaction makes the situation worse, the later reaction may not excuse the original negligence.

Courts also look at independence. An intervening cause is more likely to matter when it is separate from the defendant’s conduct, not just a normal reaction to it. A random criminal act, a sudden natural disaster, or another unexpected outside event can qualify if it is not tied closely to the original wrong.

This is where the term connects to tort reasoning instead of just everyday language. Not every later event breaks liability. The court is not asking, “Was there another event?” It is asking whether that event was so unusual, independent, and unforeseeable that it should cut off the defendant’s legal responsibility.

A quick example makes the idea easier to see. Suppose a driver negligently leaves a car blocking a lane, and another driver swerves around it and hits a pedestrian. The blocked lane may still be part of the cause chain if the second driver’s reaction was predictable. But if a completely unrelated storm or third-party attack creates a new, unexpected harm, the original negligent actor may have a stronger argument that the later event was the real legal cause.

Why intervening cause matters in Intro to Law and Legal Process

Intervening cause shows how tort law separates the first bad act from the final injury. That matters because negligence alone does not automatically mean liability for every downstream consequence. You have to connect duty, breach, causation, and damages, and intervening cause is one of the main places where causation gets tested.

This term also helps you read cases the way courts do. A judge is not just counting events in order, they are deciding whether the law should treat the defendant’s conduct as the legal cause of the harm. That means you need to notice timing, foreseeability, and whether the later event looks like a normal response or a truly separate force.

In a torts unit, intervening cause often appears right next to defenses like comparative negligence and assumption of risk, but it does something different. Those defenses focus on the plaintiff’s conduct or consent. Intervening cause focuses on a later event that may interrupt the chain between the defendant and the injury.

If you can spot an intervening cause in a fact pattern, you can explain why liability might stop even when the defendant clearly acted badly. That is a big legal reasoning move in Intro to Law and Legal Process, especially in case briefs, hypotheticals, and short-answer questions where you have to connect facts to doctrine.

How intervening cause connects across the course

proximate cause

Intervening cause is one piece of the bigger proximate cause analysis. Proximate cause asks whether the harm is legally close enough to the defendant’s conduct to justify liability. An intervening cause can affect that analysis by showing that the chain of causation was interrupted. If the later event was foreseeable, proximate cause may still be found.

negligence

Intervening cause usually comes up after you have already identified negligence. You first ask whether the defendant owed a duty and breached it, then you ask whether that breach actually and legally caused the injury. A negligence claim can fail on causation even when the conduct was careless, if a later event cuts off responsibility.

superseding cause

Superseding cause is the term you will often see alongside intervening cause, and the two are easy to mix up. An intervening cause is any later event between the defendant’s act and the harm. A superseding cause is the kind of intervening event that is strong enough to break liability. Not every intervening cause is superseding.

comparative negligence

Comparative negligence deals with sharing fault between the plaintiff and defendant, while intervening cause asks whether a later event breaks the chain entirely. If the plaintiff also acted carelessly, a court may reduce recovery under comparative negligence instead of treating the later event as a full break in causation. The two ideas can appear in the same case but do different jobs.

Is intervening cause on the Intro to Law and Legal Process exam?

A case analysis or hypothetical usually asks you to trace cause and effect and decide whether the defendant is still liable after a later event happens. You would point out the original negligent act, identify the later event, and explain whether it was foreseeable or independent enough to break the chain of causation. If the facts mention a storm, a third-party crime, or an unexpected reaction, that is your cue to discuss intervening cause. A strong answer does not stop at naming the term, it explains why the later event changes, or does not change, legal responsibility.

Intervening cause vs superseding cause

Intervening cause is any event that happens after the defendant’s act and before the injury. Superseding cause is a specific kind of intervening cause that is so unexpected or independent that it cuts off liability. In other words, every superseding cause is an intervening cause, but not every intervening cause is superseding.

Key things to remember about intervening cause

• An intervening cause is a later event that happens after the defendant’s conduct and before the plaintiff’s harm.

• The big legal question is whether that later event breaks the chain of causation and cuts off liability.

• Foreseeability matters, because a predictable later event usually does not excuse the defendant.

• A truly independent event, like an unexpected third-party act or rare outside force, is more likely to matter.

• In tort cases, you use this term when you explain why a defendant is or is not the legal cause of the injury.

Frequently asked questions about intervening cause

What is intervening cause in Intro to Law and Legal Process?

Intervening cause is a later event that happens after a defendant’s negligent act but before the injury. It can affect whether the defendant is still legally responsible for the harm. In tort analysis, you use it to test the chain of causation.

What is the difference between intervening cause and superseding cause?

An intervening cause is any event that comes between the defendant’s act and the final injury. A superseding cause is an intervening event that is strong enough to break the chain of legal causation. The easiest way to remember it is that superseding cause is the more powerful version.

Can a foreseeable event be an intervening cause?

Yes, a later event can still count as an intervening cause even if it does not break liability. If the event was foreseeable, a court may say the defendant remains responsible because the chain of causation was not legally broken. Foreseeability is what separates a harmless interruption from one that cuts off liability.

How do I spot intervening cause in a tort case?

Look for a sequence where the defendant acts first, then something else happens, and then the plaintiff is injured. Ask whether the later event was independent, unusual, or predictable. If the facts suggest a random third-party act or an unexpected outside force, intervening cause is probably part of the analysis.