Gov. Nathan Deal's expansion of the state Court of Appeals has been targeted by a legal challenge that claims his three appointments to the bench were unconstitutional because the Georgia Constitution requires they be filled by election.

The lawsuit invokes a section of the state Constitution that mandates that all "judges of the Court of Appeals shall be elected on a nonpartisan basis for a term of six years." There is no provision in the document, the lawsuit said, that allows a governor to appoint the newly-created judgeships.

Deal's administration won legislative approval this year to expand the court from 12 to 15 judges, and in October he appointed three attorneys to the new posts: Amanda Mercier, Nels Peterson and Brian Rickman.

It's part of Deal's broader plan to expand the judiciary that also includes a push next year to add two more justices to the Supreme Court's bench and a proposal to build a new courthouse to house Georgia's top judicial offices.

The lawsuit - you can find your copy here - was filed Monday in Fulton County Superior Court by Fayetteville attorney Wayne Kendall. He represents a group of plaintiffs that include Ken Dious, an Athens attorney who launched an unsuccessful bid for Congress last year, and Georgia NAACP president Francys Johnson.

The state Attorney General's office declined to comment on the pending litigation. Deal has said his proposals were designed to help the judicial branch cope with an increasing workload. But critics worry it would give the Republican too much control over Georgia's top courts.

The lawsuit asks the judge to block Deal from swearing in the three appointees and requests that the seats remain open until the legal dispute is hashed out.

It notes that in 1996 and 1999, when the Legislature agreed to grow the Court of Appeals from nine judges to 12, the new posts were filled by sitting governors rather than elections.

But this was a violation of a "clear historical and foundational precedent that the voice of the people was to reign supreme" in selecting the court's judges, said the plaintiffs.

"Any contrary authorizations by the General Assembly are repugnant to the current 1983 constitution as well as previous constitutions of this state," the lawsuit said.