COLUMBIA - Lawyers for House Speaker Bobby Harrell plan to ask a circuit judge to make a ruling that critics say could stop a grand jury investigation into the House leader.

Gedney Howe, one of Harrell's attorneys, said Tuesday that a long-running ethics-related probe into Harrell should be handled by a House panel made up of other lawmakers charged with deciding such cases - not by a state court. A hearing has been scheduled next week on the issue, Howe said.

The potential for a judge to strip the attorney general's authority to proceed with a grand jury probe was immediately decried by critics as an example of the powerful House speaker seeking to influence the outcome of a investigation into his conduct.

Harrell, R-Charleston, faces accusations that he used campaign funds for personal expenses and abused his position to benefit his company, among other things. Earlier this year, Attorney General Alan Wilson announced that a state grand jury would investigate the charges.

Judge Casey Manning has been weighing whether Wilson has a conflict of interest in the case, as Harrell's attorneys have contended. At a hearing last month, Harrell's chief of staff, Brad Wright, said Wilson had sought to intimidate him during a meeting about a piece of legislation the attorney general was supporting.

Wright testified, however, that there was no explicit quid pro quo. Harrell was never given an explicit promise that if he helped push for Wilson's legislative initiative, the attorney general would drop the ethics investigation into the speaker, Wright said. Wilson denies trying to intimidate Wright.

Manning has been expected for weeks to make a decision on whether Wilson should be removed from the case. In the meantime, Howe said that he has asked Manning to consider whether the state court has the authority to make a decision on an ethics-related case involving the Legislature.

A Wilson spokesman, Mark Powell, said that the attorney general's office has not yet been notified of a hearing date. He said that the attorney general's position would be made clear at the hearing but otherwise declined to comment.

Wilson's office had initially declined to consider the case because it needed to first be heard by the House Ethics Committee under state law. "The process must proceed as prescribed by state law," Wilson's office said in an October 2012 press release. "Should the House Ethics Committee not act, this Office is then prepared to do what is in the public's best interest."

Ashley Landess, president of the watchdog group South Carolina Policy Council, which pursued the ethics complaint against Harrell, said that the organization did not pursue a hearing in front of the House ethics panel because they did not believe the process would be fair, given the influence of the House speaker, among other factors. No complaint on the Harrell matter has been filed with the House Ethics Commission.

"In exploring the (House ethics) process, there were so many inherent flaws in the process itself that we believe would have compromised our right to due process," she said.

She also said that Wilson did not have all the facts when the 2012 press release was issued. Landess said that more facts later emerged, at which time Wilson's office decided to take on the Harrell investigation.

Harrell has denied any wrongdoing and has said that the charges against him are politically motivated.

Landess said that she fears what a Manning decision in Harrell's favor would do to those seeking to hold legislators accountable.

"If this judge were to do this, it is not an exaggeration to say the precedent would be set that legislators could commit crimes that rose to the felony level and the attorney general could be powerless to investigate those crimes," she said.

Under state law, all ethics-related cases involving a member of the General Assembly must go before the House ethics panel, Howe said.

"The ethics committee has the exclusive jurisdiction," he said. "That's the only entity with jurisdiction." He pointed to a June 2013 Circuit Court decision authored by Manning that did not allow for ethics-related charges to be pursued in a state court against Gov. Nikki Haley. Haley faced ethics allegations when she was a member of the S.C. House. She was later cleared of any wrongdoing by the House ethics panel.

"It is clear the Legislature intended the respective Ethics Committees to have exclusive authority to hear alleged ethics violations of its own members and staff," Manning wrote.

No criminal charges have been brought against Harrell. Generally, the House and Senate ethics committees consider civil penalties for alleged ethics violations. If there is evidence of criminal conduct, the committees are directed to turn over the case to law enforcement.

Still, South Carolina's Constitution gives the attorney general broad authority to pursue grand jury investigations and criminal charges of any kind, said John Crangle, an attorney and Harrell critic who heads the advocacy group Common Cause.

"It's a real stretch," Crangle said of the Harrell team's legal argument. "I've never heard of anybody trying to stop a state grand jury probe - that's basically what they're trying to do."

A hearing on the matter has been scheduled for next Wednesday, April 30, at 10 a.m., Howe said.

Reach Jeremy Borden at 708-5837.