A top campaign aide and a political operative who worked on former Maryland governor Robert L. Ehrlich Jr.’s bid to retake the governor’s mansion last year pleaded not guilty Monday to charges that they sought to use robo-calls to suppress turnout among black voters.

Baltimore Circuit Court Judge Lawrence P. Fletcher-Hill scheduled a Sept. 22 trial for Ehrlich’s de facto campaign manager, Paul Schurick, and controversial political consultant, Julius Henson. The two face multiple counts of election law violations stemming from an automated call that was placed to tens of thousands of Democrats last Election Day while the polls were still open.

According to the state prosecutor’s office, the calls to residents in predominantly black districts of Baltimore and Prince George’s County were intended to trick voters into thinking that there was no need to vote because incumbent Gov. Martin O’Malley (D) had already defeated Ehrlich (R).

Henson and Schurick spent little time together at the courthouse Monday. Neither spoke during the hearing, and the two arrived and departed separately. It remained unclear if either would seek a separate trial from the other. Attorneys for both Schurick and Henson said they had no plans to make such a motion but expected the other would do so. Indictments show a series of contacts between the two defendants before the calls were placed.

Outside the courtroom, Henson, 62, said he was “100 percent” confident a jury would find him innocent. He suggested political motivations were behind the indictments sought by State Prosecutor Emmet C. Davitt, a post-election O’Malley appointee, and a multimillion-dollar civil case brought by state Attorney General Douglas F. Gansler (D), who is expected to run for governor in 2014.

Henson also included Sen. Benjamin L. Cardin (D-Md.) among those he said were pushing for his prosecution.

“This is something by Ben Cardin, O’Malley just to punish people who disagree with what goes on in the Democratic Party,” Henson said.

“I recommend the state prosecutor read the Constitution because free speech is a protected class, especially political speech. No matter the style, it cannot be curtailed.”

Henson, who has a history of using brash campaign tactics on behalf Democratic candidates, said last fall that the calls were intended to be “counterintuitive” and to motivate Ehrlich supporters to get out and vote in the election’s waning hours.

“No law was violated. Find it.”

Schurick’s attorney, A. Dwight Pettit, also said he may challenge the prosecution on First Amendment grounds.

He said he was confident from the evidence he had reviewed that Schurick would be found “absolutely innocent.”