Sole Proximate Cause—Whose Burden Is It Anyway?
By Judge Eileen Marie O’Connor
Tort Law,
May 2026
Although a party may plead in the alternative and assert multiple theories of sole proximate cause, the trial court must serve as gatekeeper to ensure that this burden is met. Specifically, the court must ensure that the defendant presents competent evidence establishing that a third party, condition, or combination thereof constituted the sole—rather than a merely contributing—cause of the plaintiff’s injury. Absent such safeguards, the doctrine of sole proximate cause risks misapplication, inviting jury confusion and undermining the integrity of the verdict.
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