State prosecutors and defense attorneys agreed on one key revelation Tuesday in the opening statements of a trial to determine whether robo-calls made during Maryland’s gubernatorial election last year were intended to suppress black voter turnout.

Paul E. Schurick, former governor Robert L. Ehrlich Jr.’s (R) campaign manager, approved the calls, which were placed to homes of tens of thousands of African American Democrats in Prince George’s County and Baltimore while the polls were still open on Election Day.

A woman’s recorded voice told listeners to “relax” and not to worry about voting because the incumbent, Gov. Martin O’Malley (D), and President Obama had already been “successful” in the day’s voting.

Until Tuesday, it was unclear how high in Ehrlich’s campaign the order to place the calls had originated. An outside consultant, Julius Henson, who has been indicted with Schurick in the case, had publicly taken responsibility for them. But Schurick, whose trial began Monday, told an FBI agent that he approved the calls.

That, however, is where agreement about the calls ends.

State Prosecutor Emmet C. Davitt cast Schurick’s approval of the robo-calls as the culmination of a months-long criminal conspiracy by a campaign manager acutely aware of how turnout by black voters could affect the election.

Davitt, an O’Malley appointee, urged jurors to consider the words of the recorded message and the fact that it targeted Democrats as the main evidence of the case. He said “common sense” should be used when evaluating an explanation offered in Schurick’s defense. The calls were a kind of reverse psychology, Schurick’s attorney said, intended to motivate Democrats inclined to cross party lines and vote for Ehrlich to head to the polls in the election’s waning hours.

Davitt said the calls were intended to do something far more sinister and to interfere with the country’s “sacred ritual” of voting. “It’s not just a dirty political trick,” Davitt said. “In the state of Maryland, it’s against the law.”

Schurick’s lead attorney, A. Dwight Pettit, said he would prove that no such conspiracy existed.

Pettit said other members of Ehrlich’s campaign team will attest that Schurick previously rejected a plan by Henson to suppress black voter turnout. And on Election Day, Pettit said, Schurick’s approval of the robo-calls came in response to Henson’s assertion that the calls would motivate a few final supporters to turn out for Ehrlich.

Pettit also characterized Schurick’s approval of the recorded message — which he said his client did not listen to until after the election was over — as one of countless decisions made by the campaign manager in the fog of a busy Election Day. He said that in a state dominated by Democratic politics, prosecutors had gone overboard and grasped at straws to build a case.

“The heavy arm of the state came down across the Republican Party,” Pettit said.

Before opening statements, Schurick, 55, received a bit of good news. Baltimore City Circuit Court Judge Lawrence P. Fletcher-Hill threw out one of three conspiracy charges, siding with Schurick’s defense team that the charges were duplicative.

Schurick still faces charges of conspiracy to suppress voting and conspiracy to withhold an “authority line” from the robo-calls, which did not include the mandatory acknowledgment that Ehrlich’s campaign had paid for them.

He also faces one charge of obstruction of justice. Prosecutors allege that Schurick did not turn over a portion of a document — drafted by Henson and titled the “Schurick Doctrine” — that called for targeting black districts for voter suppression.

Davitt and Deputy State Prosecutor Thomas M. McDonough contend that the document planted the seed that ultimately produced the robo-calls. Prosecutors have not suggested that Ehrlich had any advanced knowledge of the calls or the so-called doctrine.

Davitt read aloud from the document, which said its “first and most desired outcome” was voter suppression.

In a twist that could cut for or against the prosecution, one of Davitt’s first witnesses, a Baltimore Democrat, said the call did, in fact, inspire him and his wife to run out and vote — but for O’Malley, because the call was viewed as a dirty trick.