A federal judge in Orlando on Wednesday declared the state’s controlled-substances laws unconstitutional. A 2002 Florida law eliminated the requirement of a “guilty mind,” or “mens rea,” as part of a drug offense. Briefs attacking the Florida law, in which a defendant need not know that a substance is illegal to be convicted of possessing or selling it, had been filed by groups including the National Association of Criminal Defense Lawyers, the American Civil Liberties Union and dozens of law professors. Judge Mary S. Scriven of Federal District Court threw out the drug delivery charges against Mackle Vincent Shelton, and ordered a new sentencing hearing on other charges. Florida’s unique law expressly eliminating mens rea for drug offenses, the judge wrote, is “atavistic and repugnant to the common law.” The state is expected to appeal the decision, which could leave hundreds, if not thousands, of convictions in question and affect pending cases.