In the United States Supreme Court case of The United States v. Joseph Delespine, the court was asked to decide whether a defendant could be convicted for an offense that had been committed prior to Congress passing a law making it illegal. In this particular case, Joseph Delespine had been charged with selling liquor without having paid taxes on it as required by federal law. However, at the time he sold the liquor there was no such requirement in place and thus his conviction rested upon whether or not he could be held liable for violating a law which did not exist when he committed his crime. Ultimately, the Supreme Court ruled that since there was no existing statute prohibiting what Mr. Delespine had done at the time of his actions, he could not be found guilty under those laws and therefore must have his conviction overturned. This ruling established an important precedent regarding criminal liability and set forth legal principles still used today in determining if someone can be held accountable for their past behavior even if they were unaware of any applicable laws at that time

In the United States v. Joseph Delespine, the Supreme Court was tasked with deciding whether a defendant could be convicted of an offense that had been committed before Congress passed a law making it illegal. The majority opinion held that since there was no law in place at the time of commission, Delespine could not be found guilty and his conviction should therefore be reversed. However, Justice McLean dissented from this decision on two grounds: firstly, he argued that if Congress has authority to pass laws retroactively punishing offenses already committed then they can do so; secondly, he argued that even if such legislation is unconstitutional or otherwise invalid under existing laws then it still stands as valid until declared void by competent judicial authority. In conclusion, Justice McLean believed Delespine's conviction should stand because although Congress may have acted unconstitutionally in passing retroactive legislation to punish him for an act which occurred prior to its passage into law - this did not render his conviction null and void until declared so by a court of competent jurisdiction.