The U.S. Supreme Court has declined to intervene in Thursday’s execution of Alabama convict Kenneth Smith, who’s slated to become the first person in the country put to death with nitrogen gas. No opinion was issued by the justices, who decided against reviewing Smith’s case the day before his scheduled execution. The U.S. 11th Circuit Court flat-out rejected Smith’s argument against execution by nitrogen hypoxia Wednesday. The Supreme Court could have still decided to review that federal appellate court’s ruling, according to Alabama outlet AL.com. Mississippi and Oklahoma joined Alabama in l…