State lawmakers who break the law while performing their official duties cannot be prosecuted, lawyers for Sen. Don Balfour asserted in court on Friday.

That’s a theory Assistant Attorney General Gregory Lohmeier called “completely repugnant to our system of government.”

“What he is saying is that General Assembly members are above the law,” Lohmeier said.

Attorney William Hill Jr. said the state Constitution gives the power to discipline senators exclusively to the Senate. A Fulton County grand jury indicted Balfour, R-Snellville, in September on 18 felony counts related to legislative expense reports he filed over a four-year period.

“In this indictment Sen. Balfour is being charged with misconduct in his capacity as a state senator,” Hill said. “Sen. Balfour is not being charged with a crime in his capacity as a citizen.”

Only the Senate can punish its members for official acts of wrongdoing, Hill said. Balfour claims he submitted the expense reports by mistake. Last year the Senate Ethics Committee fined Balfour $5,000 and ordered him to repay about $350.

“There is an entire scheme (in the General Assembly) that the Senate uses to punish its own,” he said.

In a motion argued Friday, Hill asked Fulton County Superior Court Judge Henry Newkirk to dismiss the indictment as a violation of the constitutional doctrine separating the three branches of government. Newkirk, who is to preside over the planned Dec. 16 trial of the long-serving lawmaker, said he would rule shortly.

Lohmeier, who is handling the prosecution for Attorney General Sam Olens, said Hill is trying to twist the Constitution in such a way as to allow lawmakers to evade prosecution for laws they themselves passed.

“The state attorney general’s office is all about the separation of powers,” he said. “We’re not trying to say it doesn’t exist.”

But while the Constitution says the Legislature has the power to punish its members for misbehavior, it does not protect lawmakers from further criminal prosecution.

“It doesn’t say the state attorney general or the district attorney is prohibited from coming in and punishing someone for committing a crime,” he said.

If that were the case, it would have “far-reaching implications,” he said.

In the hearing, Newkirk wondered about the limit to Hill’s argument.

“Senators have gotten angry at each other. What if one walked over and cold-cocked another in the head?” he said.

After the hearing, Hill addressed the hypothetical. “I daresay that may have happened in the past. I’m not aware of any prosecutions for that,” he said. “I think that would be in the purview of the Senate.”

The trial is a little more than a week away. Any significant delay could mean Balfour, who did not attend Friday’s hearing, would be allowed to resume his duties when the Legislature convenes Jan. 13.

Gov. Nathan Deal suspended Balfour from office last month on grounds that he had been indicted on felony charges, but the state Constitution terminates the suspension if he is not tried by the next legislative session.

Balfour requested a speedy trial and Hill said the senator is eager to clear his name. But he also urged Newkirk to grant his motion and let the Attorney General’s office “appeal it rather than put my client through a trial.”

If the trial is delayed, Balfour can expect a chilly reception from his Senate colleagues. After his suspension, Senate Republicans kicked him out of their caucus and stripped him of all of his leadership positions. After 21 years in office, he would have all the clout of a freshman.