Also known as: chains of causation · causal chain · causal chains · causation chain
Written by attorneys · grounded in primary & secondary sources — see below
A sequence of events each produced by the one before it that connects an initial act or condition to a later harm or result. The connection supplies the factual and legal link required for liability or constitutional authority when the sequence remains unbroken by an independent or superseding event.
Clifford Cox received a prescription drug from his physician after the manufacturer had warned the doctor of known risks. When Cox suffered an adverse reaction, he sued the manufacturer for failure to warn. The physician's independent decision to prescribe despite the warnings operated as an intervening judgment that severed any direct causal sequence from the manufacturer to the patient.
Carmen Choi displayed a symbol that city officials claimed would provoke fights. The ordinance targeted only symbols conveying a particular message. Because any violence would arise solely from the message's persuasive force rather than from separate conduct, the causal sequence ran through protected speech and invalidated the selective regulation.
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Cecilia Cabrera was arrested without probable cause and later confessed after receiving Miranda warnings and meeting with family. The passage of time and the warnings did not interrupt the direct sequence from the unlawful arrest to the statement. The confession therefore remained the product of the initial illegality and was suppressed.
Colin Chambers continued smoking after learning that advertisements about a product's safety were false. His continued use despite that knowledge inserted an independent decision that severed the sequence between the manufacturer's breach of warranty and his resulting illness.
Christine Castro sold counterfeit bills to a counterfeiter who then passed them to others. Because Castro did not participate in or seek to further the specific passing venture, her conduct did not form part of the causal sequence required for accessory liability.
Chloe Chen's competitor claimed lost sales after Static Control sold components that enabled refurbished cartridges. The asserted injury depended on multiple downstream business decisions by third parties. That attenuated sequence failed to supply the required causal link between the defendant's conduct and the claimed harm.
An intervening act breaks the chain when it is independent, unforeseeable, and not a normal response to the original conduct. Dependent or responsive acts generated by the initial conduct, such as a police pursuit after high-speed flight, ordinarily do not sever the sequence.
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A statute exceeds commerce power when its connection to interstate commerce rests on a speculative, multi-step chain of inferences from non-economic local conduct to downstream economic effects. Courts reject such attenuated sequences as insufficient to establish a substantial effect on commerce.
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A buyer's knowledge of a warranty-breaching defect can break the chain if the buyer proceeds with use despite that knowledge. The independent decision to continue use severs the link between the breach and the resulting personal injury.
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The prescribing physician's independent medical judgment breaks the causal chain between a drug manufacturer and the patient when the manufacturer has adequately warned the physician. Absent inadequate or misleading warnings to the physician, the manufacturer is not liable for failure to warn the patient.
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…authority seems well founded. See Lopez, supra , at 564. The reasoning that petitioners advance seeks to follow the but-for causal chain from the initial occurrence of violent crime (the suppression of which has always been the prime object of the States' police power) to every attenuated effect upon interstate commerce. If…