## Facts

- Los Angeles required any “convicted person” to register with the Chief of Police if present in the city for more than five days; each day of nonregistration was a separate offense.
- Lambert had lived in Los Angeles for over seven years and had a prior felony conviction for forgery in California.
- Lambert never registered under the ordinance.
- After being arrested on suspicion of another offense, Lambert was charged with violating the registration ordinance.
- At trial, Lambert challenged the ordinance under the Fourteenth Amendment and sought to prove she lacked actual knowledge of the duty to register; the court rejected the challenge and excluded the evidence.
- Lambert was convicted, fined, and placed on probation; state courts affirmed.
- The U.S. Supreme Court granted certiorari and reversed.

## Issues

1. Whether due process permits conviction for failure to comply with a registration ordinance when the defendant lacked actual knowledge of the duty and there was no showing of the probability of such knowledge.

## Decision

- The Supreme Court reversed Lambert’s conviction.
- Due process was violated as applied because Lambert’s offense was a wholly passive failure to act, with no evidence she knew or likely should have known of the registration duty.
- The Court held that, in this setting, conviction requires either actual knowledge of the duty to register or proof of the probability of such knowledge.

## Legal Principles

- Due process requires fair notice before criminal punishment may be imposed for a passive omission that is not accompanied by circumstances likely to alert a reasonable person to inquire about a legal duty.
- In prosecutions for failure to register under this type of ordinance, the government must show actual knowledge of the duty to register or the probability of such knowledge.
- The general maxim that ignorance of the law is no excuse does not control where liability is based on mere presence and an unknowing failure to act, absent circumstances suggesting wrongdoing or a duty to act.

## Conclusion

The Court held that imposing criminal liability for Lambert’s passive nonregistration, without actual notice or a showing that she probably knew of the duty to register, denied due process because it lacked fair warning and a realistic opportunity to comply.


Lambert v. California, 355 U.S. 225 (1957)