PHOENIX — State senators voted Monday to expand Arizona’s Supreme Court in what one Democrat lawmaker called a “power grab” by Gov. Doug Ducey.

HB 2537, approved on a 18-12 party-line vote, would add two more justices to the current five-member panel. A final roll-call vote will send the measure to the governor.

Ducey, who made one high court appointment earlier this year, has not discouraged the move to give him the opportunity to select two more justices — even if that means increasing the cost to taxpayers of running the judiciary.

“We have made our government more efficient,” the governor said Monday when asked about the move to increase the size of the court.

Justices are paid $155,000 a year, plus a package of fringe and retirement benefits that probably brings the cost close to $200,000. And each justices has a judicial assistant and two law clerks who also are paid.

But the governor sidestepped the question of why it makes sense to spend more tax dollars on the court, saying only there “certain services” that need to grow because of the increasing size of the state, things like K-12 education.

Sen. Steve Farley, D-Tucson, sees something more sinister in the maneuver, saying no one — including the current justices on the court — is asking for the expansion.

“The only reason why you would add justices to the court is to pack the court for political reasons,” he said.

“This is the executive making a power grab over the judiciary,” Farley continued. “If you don’t like the decisions the Supreme Court is making, you don’t pack the court.”

Sen. Martin Quezada, D-Phoenix, said the numbers do not justify an expansion.

He said Arizona has one justice for every 1.3 million residents. By contrast, Quezada said California, with seven on its high court, has one justice for every 5.5 million residents.

But Sen. John Kavanagh, R-Fountain Hills, had his own set of figures.

He said Vermont, with just 626,000 residents, has the same number of justices as Arizona. Based on that, Kavanagh said, Arizona would need many more justices to keep the same ratio.,

“But we’re only going to add two,” he said.

Four of the five justices were named by Republican governors, though Ducey, in his first pick, chose Clint Bolick, who was a registered political independent. Chief Justice Scott Bales, selected by Janet Napolitano when she was governor, is the court’s lone Democrat.

Republican senators who supported the move denied it had anything to do with putting more Republicans on the court.

Senate President Andy Biggs, R-Gilbert, said additional justices are needed not just because of the growth of the state but due to increased litigation. And Sen. Don Shooter, R-Yuma, said more justices will lead to more justice.

“In a multitude of counselors, there is wisdom,” he said.

But Farley said that’s just a convenient excuse by GOP lawmakers to give the GOP governor additional influence on the court.

Justices technically serve for six-year terms, at which time they stand for a re-election, not facing any other candidate but on a retain-or-reject basis.

No Supreme Court justice who has sought a new term has been turned out of office since that system was put in place by voters in 1974.