Robinson (defendant) was convicted under a California statute that made it illegal for someone to be addicted to drugs. Four months prior to his conviction, a Los Angeles officer had found scars and needle marks on both of Robinson’s arms. Robinson at the time admitted that he had previously used narcotics. At trial, the judge instructed the jury that it could convict Robinson if it either found that he used drugs in California or found he was addicted to drugs. The jury’s verdict read “guilty of the offense charged." The appellate court affirmed Robinson's conviction, and Robinson sought review from the United States Supreme Court.