She didn’t fire the BIL trooper. She fired the Commissioner. The Commissioner claims that Palin pressured him to fire the BIL, which he wouldn’t do. Palin says she never pressured him to fire anyone. She says they just gave him information about the guy’s troublesome behavior.
IMO, the comissioner should have been fired if he lets guys like that carry a badge. The trooper Union is powerful in the state.
One slight correction. On the day this story broke, both Sarah and the commissioner said that Sarah did not pressure the commish to fire the BIL. Rather, the pressure came from Sarah's husband Todd.