The Florida Supreme Court decided on Wednesday that the state can proceed with the execution next week of a 64-year-old inmate named John Ferguson. His lawyers immediately said that they will ask the United States Supreme Court to stay the execution and to review the case on grounds that Mr. Ferguson is mentally incompetent and that executing him would violate his constitutional rights as defined by the court in two earlier decisions.

The court must review the case. At issue are not only Mr. Ferguson’s life but also two differing interpretations of what constitutes competence: one Florida’s, the other the Supreme Court’s.

Mr. Ferguson believes that he is the Prince of God and that he is facing execution not for murders he committed but because of a conspiracy against him for being the prince. He believes that he cannot be killed and that he has “inner ears” so he can hear God whisper instructions. All of this is consistent with his being a paranoid schizophrenic, as he was diagnosed 40 years ago and many times since, including earlier this month.

The Supreme Court ruled in 1986 that it is unconstitutional to execute someone who lacks the “ability to comprehend the nature of the penalty.” In 2007, the court clarified that a “prisoner’s awareness of the state’s rationale for an execution is not the same as a rational understanding of it” and that evidence of psychological dysfunction may result in a “fundamental failure to appreciate the connection” between his crimes and his execution.