While Governor Perry would probably be happy to take full credit for the firm stand, unless the Texas Constitution has been changed recently, his only independent power related to executions is to grant one (1) 30 day stay of execution.
Except for that one time action, the governor is powerless to do anything on his own. A state Pardons and Paroles Board, appointed by the governor, must recommend any action for the governor to take. The governor does not have to follow the recommendation but he can’t act without it. We often have some very independent minded people on these type boards.