As far as I know, this is the first time in U.S. history that an execution has been halted due to a subpoena.
> The all-Republican court's decision comes in response to a first-of-its-kind legal maneuver in which a House committee voted to subpoena Roberson after his scheduled death.
> The all-Republican court's decision comes in response to a first-of-its-kind legal maneuver in which a House committee voted to subpoena Roberson after his scheduled death.
See also https://time.com/7094361/texas-supreme-court-halts-execution...