The controversial execution of a Texas man convicted in a so-called “shaken baby syndrome” murder case was delayed with just 90 minutes to spare before his scheduled lethal injection Thursday night, but the outcome is still very much in limbo. A group of bipartisan state lawmakers had petitioned the state to grant Robert Roberson clemency, and after that request was denied, they took what NBC News refers to as the “unusual step” of issuing a subpoena for Roberson to testify at a hearing regarding his case next week—an effort to disrupt the execution that worked, at least temporarily. Roberson …