However, in Robertson's case, the charged offenses in the federal and state prosecutions were the same, the court's opinion said. The ruling noted that Robertson was charged in both courts with possession of child pornography, and the definition of "child pornography" is the same under both statutes.
"And though the federal offense requires proof of an element that the Utah statute does not interstate commerce the Utah statute does not require proof of an element that the federal statute does not," the ruling said.
The opinion reversed a Court of Appeals decision that upheld the 2012 conviction.
Robertson, now 66, the owner and manager of a heating and air conditioning company, was arrested in 2009 after employees reported that he was openly viewing child pornography on his computer.
The Utah Internet Crimes Against Children Task Force seized his computers and found 24,447 images and 386 videos containing child pornography. According to court records, the state sought federal prosecution to obtain a more severe sentence.
Robertson was indicted by a federal grand jury on one count of possession of child pornography and pleaded guilty to the crime. He faced a maximum sentence of 10 years in prison, but U.S. District Judge Clark Waddoups imposed a sentence of two days in jail plus time served.
Utah prosecutors then charged Robertson in state court with 20 counts of sexual exploitation of a minor. He was convicted in a bench trial and was sentenced to 20 concurrent terms of one to 15 years behind bars. After the Court of Appeals upheld the conviction, the case went to the Supreme Court.
In an October 2015 hearing, Robertson's lawyer Elizabeth Hunt argued that Utah law does not allow a defendant to be charged in state court after being prosecuted on the same evidence in another state court or in federal court. Assistant Utah Attorney General Jeffrey Gray countered that the federal and state cases were separate prosecutions based on different laws and different evidence.
Daniel Burton, a spokesman for the Utah attorney general's office, said Tuesday that the office is reviewing the opinion and had no comment.
In addition to ruling that the state was prohibited from prosecuting Robertson, the opinion also overruled part of an earlier decision handed down by the Utah Supreme Court in the case of Joseph Paul Franklin, a serial killer who shot to death two black men in Salt Lake City in 1980.
Franklin was convicted of civil rights violations in federal court and murder charges in state court. He appealed, and the Supreme Court ruled in 1987 that the separate prosecutions were justified.
In the Monday ruling, the Supreme Court said it had overruled its earlier conclusion that the law incorporated the dual sovereignty doctrine.
"It is worth noting that, even though we overrule Franklin in part today, the State still remains free to prosecute a defendant so long as it is either the first jurisdiction to do so or the Utah offenses are not the same as those for which the defendant has already been prosecuted," the opinion said.
Franklin was sentenced in the state and federal cases to life in prison. He also was convicted of numerous crimes around the country, including seven other murders, and was executed in Missouri in 2013.