That is why Perry wanted Lehmberg to resign. If she had resigned, Perry could have appointed her replacement and he would have appointed someone that would squash the Delay prosecution before it would be heard by the State Court of Criminal Appeals.
[emphasis added]
Perry's veto threat and subsequent veto had no possible relationship to Lehmberg's appeal of the Delay case to the Court of Criminal Appeals.
Perry exercised his line-item veto on June 14, 2013. It was not until September 19, 2013 that the 3rd Court of Appeals overturned Delay's conviction.
Apart from its impossibility, why would you conjecture this motive on Perry's part? If it had been true, then Perry would have criminal liability. Is that what you are attempting to imply?
So, the key date is the date that that State Court of Criminal Appeals would hear the case.