Introduction

Intoxication as a Defense

Introduction

Model Penal Code § 2.08(1) states the starting rule for every intoxication problem: "Except as provided in Subsection (4) of this Section, intoxication of the actor is not a defense unless it negatives an element of the offense."¹ The sentence makes two moves. Its main clause denies intoxication any standing as a free-standing excuse, so a defendant cannot succeed by showing only that she was drunk, high, or otherwise impaired when she acted. Its qualifying clause admits that impairment can still matter when it bears on an element of the offense, which in practice usually means the mental state the offense requires. Both moves follow from the structure of a criminal trial. A person who chooses to become impaired is not forgiven what follows, yet the State must still prove every element of the charge, including the mental state, and evidence that makes that mental state less likely cannot be shut out merely because the defendant's own drinking caused the gap.

The second move depends on a distinction between an excuse and an element-negating fact. A defense in the strict sense concedes that the prosecution proved every element and asks the law to forgive the result. Evidence that negatives an element asks the factfinder to conclude that the prosecution's own case has a hole, because the mental state the offense demands was absent when the defendant acted. The argument that the defendant would never have done this when sober therefore fails, just as a violent defendant gets no relief by pointing to an excitable temperament.² The rule's opening qualification, which excepts Subsection (4), flags a separate path for intoxication that is not self-induced or that is pathological. That kind of intoxication can operate as an affirmative defense, meaning one that excuses liability even when every element is proved, if it leaves the actor without substantial capacity to appreciate the wrongfulness of the conduct or to conform it to the law.³ Later sections teach that path, and the ordinary case of voluntary intoxication is governed by the main clause.

The present-day approach sits oddly beside the law's older starting point. Most jurisdictions now admit evidence of voluntary intoxication for limited purposes, such as showing that a defendant was too impaired to premeditate or to form a specific intent, and they decline to treat it as a stand-alone excuse.⁴ Yet at an earlier time voluntary intoxication was no defense at all and could even be treated as an aggravating factor deserving harsher punishment, and only during the nineteenth century was it reformulated into a defense.⁵ A legal system that began by punishing the drunk more severely came to let the drunkenness into the trial, and the reason is historical. The next section traces how the early common-law rule gave way. After it, this chapter works through the definitions and mental-state rules of § 2.08, the statutes in some states that bar the evidence altogether, and the separate path for involuntary intoxication and its relation to insanity.⁶