The state is preparing to challenge a recent ruling that delivered former Gov. Rick Perry his first major victory in fighting the felony indictment against him. 

The Office of the State Prosecuting Attorney, led by Lisa McMinn, plans to appeal the decision last month by a state appeals court that dismissed one of the two charges facing Perry, now a presidential candidate.

"We're just defending the statute that the 3rd Court of Appeals struck as unconstitutional," McMinn said Wednesday, declining to comment further. 

Last month, the 3rd Court of Appeals threw out the charge that Perry coerced a public servant when he threatened to veto state funding for a unit of the Travis County district attorney's office. The Austin-based court argued that Perry's threat was protected by the First Amendment. 

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In doing so, the 3rd Court of Appeals invalidated a part of the Texas penal code that defines coercion. That caught Michael McCrum, the special prosecutor handling the indictment, by surprise.

"I think it's going to have some far-reaching effects," he said at the time, wondering aloud whether all those found guilty under the statute would now have a basis to challenge their convictions.

Tony Buzbee, Perry's top lawyer in the case, said Wednesday that it makes sense the state would challenge the ruling, which calls into question a law under which the state has already prosecuted people. "But," he added in an email, "that doesn't change the fact that the statute is unconstitutional." 

McMinn's office represents the state before the Court of Criminal Appeals. It has 30 days after a ruling to file what is known as a petition for discretionary review.  

The office's decision is the latest development in a legal saga that began about a year ago, when a Travis County grand jury handed up the indictment against Perry. The case centers on his threat to veto state funding for the public integrity unit unless Travis County District Attorney Rosemary Lehmberg stepped down following a drunken driving arrest. At the time, Lehmberg's office housed the unit, which handles ethics complaints against statewide officials. 

Disclosure: Tony Buzbee was a major donor to the Tribune in 2012. A complete list of Tribune donors and sponsors can be viewed here.