Courts have used a number of analytical approaches to determine when an intervening act absolves the accused of legal responsibility for manslaughter. For example, both the “reasonable foreseeability” and the “intentional, independent act” approach may be useful in assessing legal causation depending on the specific factual matrix. These approaches grapple with the issue of the moral connection between the accused’s acts and the death; they acknowledge that an intervening act that is reasonably foreseeable to the accused may well not break the chain of causation, and that an independent and intentional act by a third party may in some cases make it unfair to hold the accused responsible. These approaches may be useful tools depending upon the factual context.
However, the analysis must focus on first principles and recognize that these tools are analytical aids and do not alter the standard of legal causation or substitute new tests. Even in cases where it is alleged that an intervening act has interrupted the chain of legal causation, the causation test remains whether the dangerous and unlawful acts of the accused are a significant contributing cause of the victim’s death.
The reasonable foreseeability approach questions whether it is fair to attribute the resulting death to the initial actor and posits that an accused who undertakes a dangerous act, and in so doing contributes to a death, should bear the risk that other foreseeable acts may intervene and contribute to that death.
The time to assess reasonable foreseeability is at the time of the initial unlawful act, rather than at the time of the intervening act as it is too restrictive to require that the precise details of the event be objectively foreseeable. It is the general nature of the intervening acts and the accompanying risk of harm that needs to be reasonably foreseeable. The intervening acts and the ensuing non‑trivial harm must be reasonably foreseeable in the sense that the acts and the harm that actually transpired flowed reasonably from the conduct of the accused. If so, then the accused’s actions may remain a significant contributing cause of death.
Whether an intervening act is independent is sometimes framed as a question of whether the intervening act is a response to the acts of the accused. In other words, did the act of the accused merely set the scene, allowing other circumstances to (coincidentally) intervene, or did the act of the accused trigger or provoke the action of the intervening party? If the intervening act is a direct response or is directly linked to the accused’s actions, and does not by its nature overwhelm the original actions, then the accused cannot be said to be morally innocent of the death.
Source: R. v. Maybin, 2012 SCC 24