Why do public welfare offenses sometimes not require proof of criminal intent?

Public welfare offenses do not require proof of criminal intent—a concept known as mens rea—primarily due to the legal principle of expediency.12

In Anglo-American law, these are often classified as strict liability offenses. The rationale is that requiring the prosecution to prove a defendant's intent or negligence for regulatory matters—such as laws governing public health, alcohol, tobacco, firearms, or traffic—would render such legislation largely ineffective and unenforceable. If individuals could successfully plead ignorance of the law in these regulatory contexts, the statutes would lose their practical utility.21

However, this approach is not without ethical controversy. Critics argue that imposing criminal convictions without evidence of moral culpability raises significant issues of justice, as it exposes citizens to state condemnation for acts that may lack actual intent or fault. Consequently, many suggest that the objectives of such regulations might be more appropriately and ethically achieved through civil sanctions, such as fines or the revocation of licenses.2