Also known as:unlawful use doctrine · unlawful use
Written by attorneys · grounded in primary & secondary sources — see below
A category of preparatory conduct recognized as a substantial step in the law of criminal attempt. It arises when a defendant possesses materials to be employed in the commission of a crime that are specially designed for such unlawful use or that can serve no lawful purpose of the actor under the circumstances.
Sources & Authorities
How it applies
Common Examples
2
Toxic Solvent in Plastics Plant
Dustin Donovan entered the Apex Plastics factory after hours carrying a custom attachment device built to fit only the chemical injection line and a locked case of highly toxic solvent. The solvent had no approved use in any plant process and Donovan offered no legitimate explanation for its presence. Security discovered the items near the line before any contamination occurred. Because the materials were specially designed for unlawful use and served no lawful purpose under the circumstances, Donovan's possession constituted a substantial step supporting attempt liability.
Lockpicks at Bank Vault
Alex Rivera was found in the alley behind First National Bank at 2 a.m. carrying a set of custom lockpick tools machined to bypass the vault's secondary deadbolt and a diagram of the alarm wiring. The tools had no other commercial or hobby use and Rivera gave no plausible innocent reason for their presence near the service entrance. Police recovered the items before any entry occurred. Because the materials were specially designed for unlawful use and served no lawful purpose under the circumstances, Rivera's possession constituted a substantial step supporting attempt liability.
Select any source to read its text and confirm it supports the definition.
Model Codes
Study Supplements
Common questions
Frequently Asked
3
What makes possession of materials a substantial step under this doctrine?+
Possession qualifies when the materials are specially designed for the crime or serve no lawful purpose for the actor under the circumstances. The possession must strongly corroborate the defendant's criminal purpose. Courts examine whether the items have any innocent function in the specific setting.
Supporting sources
Does the doctrine require that the defendant begin the final act of the crime?+
No. The doctrine treats possession of specially designed or purpose-less materials itself as a substantial step. Liability attaches before the defendant completes the target offense or even begins its final physical act.
Supporting sources
How does the doctrine distinguish ordinary tools from criminal materials?+
Ordinary tools with common lawful uses usually do not satisfy the doctrine. Materials that are custom-built for the crime or have no legitimate function for the defendant in context cross the line because they provide strong evidence of intent.
Supporting sources
545 U.S. 913 (2005)Computer Law
…Opinion of Justice Souter The question is under what circumstances the distributor of a product capable of both lawful and unlawful use is liable for acts of copyright infringement by third parties using the product. We hold that one who distributes a device with the object of promoting its use to infringe copyright, as…
Constitutional LawThe nature of judicial review · Judicial review in operationUBEFoundational