Introduction

Proximate Cause and Divergent Results

Introduction

Model Penal Code § 2.03(1) says when conduct is the cause of a result, and it builds the answer in two layers.¹ Paragraph (a) requires that the conduct be an antecedent but for which the result would not have occurred. Paragraph (b) then requires that the relationship between conduct and result satisfy any additional causal requirements imposed by the Code or by the law defining the offense.² But-for causation is taught elsewhere, and here it is only the threshold the defendant has already crossed. The Code needs a second layer because but-for reasoning has no natural stopping point. Every earlier event without which the harm would not have happened qualifies, however distant, so the test alone cannot separate the person who should answer for a harm from everyone whose conduct merely sits upstream of it.³

The second layer matters only for result crimes. Perjury, forgery, and reckless driving are complete without any particular consequence, so they raise no causation problem. Murder, battery, arson, manslaughter, and negligent homicide each require a specified result, and for them the problem is real.⁴ A death can be a but-for consequence of what the defendant did and still arrive by a route no one expected, and the question is whether it is fair to blame the defendant for it. The Code treats that as a question of culpability: how far should liability extend, given what the actor purposed, knew, or risked? Its drafters grounded the provision in the view that but-for causation is the only strictly causal requirement imposed generally, and that what remains is the proper scope of liability in light of the actor's culpability.⁵

That idea organizes everything that follows. The actual result must fit the actor's purpose, knowledge, or risk, or it must differ from them only in ways that leave the actor's blameworthiness unchanged, such as a different victim or the same kind of harm arriving by a path that is not too remote or accidental.⁶ The drafters wrote the provision in general terms instead of cataloguing every divergent event, which leaves the trier of fact to use common sense in deciding whether the result bears on the defendant's culpability.⁷ Because the inquiry is tied to mental state, "causation" in this setting is a term of art whose content shifts with the culpability the offense requires.⁸ This chapter therefore starts with § 2.03(1)(b) and that idea. It then follows the Code through purposeful and knowing results, reckless and negligent results, and absolute liability offenses, and ends with a sequence for working a causation problem.