Several high-ranking Maryland government officials have testified in federal court in recent weeks that they had no idea that Sen. Ulysses Currie was being paid by a grocery chain that stood to benefit from his high-level intervention.

Yet, some of the same witnesses suggested that the efforts of the once-powerful Prince George’s Democrat had little, if any, influence on the outcome of proposed development deals, traffic light requests and other projects supported by Shoppers Food Warehouse.

Ultimately, it will be up to a dozen jurors to sort through weeks of complex testimony to determine whether Currie was taking bribes, as federal prosecutors allege, or whether his actions were more benign.

Prosecutors, who are expected to rest their case Monday, say that under the guise of a consulting arrangement, Currie was paid $245,000 to do a variety of favors for Shoppers over a period of more than five years, essentially selling his office for the benefit of the company.

This week, jurors will begin hearing from defense witnesses as Currie’s legal team makes its case. Currie’s attorneys say that his work for Shoppers might have been an “undisclosed conflict of interest” but that it did not amount to criminal behavior that could result in a prison sentence for the 74-year-old lawmaker, who has battled prostate cancer.

The first three weeks of the trial in U.S. District Court in Baltimore suggest that jurors have no simple task ahead. They have heard alternately head-spinning and mind-numbing testimony involving seven existing or proposed Shoppers locations. They heard from officials spanning two gubernatorial administrations and about numerous state and local agencies. At one point, prosecutors used the testimony of a state delegate as a mini-tutorial on how a bill becomes a law in Maryland.

Jurors have learned that Currie failed to disclose his relationship with Shoppers on state ethics forms but that he did report the consulting income on his federal tax returns — and that his work for Shoppers was not a secret among grocery executives. It is not unusual for Maryland lawmakers to have outside employment.

“It can get very confusing,” said Daniel J. Hurson, a Washington area lawyer who has prosecuted and defended white-collar criminal and political corruption cases. “Most jurors ignore all the legal niceties and try to figure out if the guy took a bribe. To win these kind of cases, the government really has to nail it on the issue of intent. . . . A jury has to be convinced there was an underhanded scheme.”

The Currie case lacks the drama of other public corruption cases recently in the news. Unlike an investigation into former Prince George’s county executive Jack B. Johnson (D), there have been no incriminating wiretaps made public or evidence of cash stashed in an accomplice’s underwear.

Instead, prosecutors have tried to build a methodical case that the arrangement between Currie and two grocery store executives, both of whom also are on trial, was corrupt. Testimony by prosecution witnesses has left some open questions about Currie’s motivations and the impact of his actions.

One prosecution witness — former Maryland transportation secretary John D. Porcari — was typical in that respect. Porcari, now deputy secretary of the U.S. Department of Transportation, last week described overtures that Currie made in 2007 for state funds to improve an interchange off the Capital Beltway at Ritchie-Marlboro Road.

At the time, Shoppers was in negotiations with the developer of a shopping center planned for the location to build a grocery store. State funds would have offset part of the cost borne by the developer to improve the interchange.

Porcari, who was appointed by Gov. Martin O’Malley (D), testified that Currie requested a meeting at which the senator asked Porcari to award a rare “secretary’s grant” of $2 million to $3 million for the improvements.

Porcari said Currie did not disclose that he was paid by Shoppers, a fact he would have considered “very germane,” likely prompting him to have a state lawyer attend the meeting.

Porcari told jurors he assumed Currie was interested because the development is in his legislative district. There had been more accidents and congestion at the interchange than expected, and Prince George’s “did and does” need economic development projects, Porcari said.

The result would have been no different had Currie not interceded, Porcari suggested. Porcari turned down the grant request, and there is still no Shoppers at the site. Currie did not put pressure on him to reverse his decision, he said.

“Senator Currie has always been very courteous and professional,” Porcari said, echoing other prosecution witnesses.

Earlier in the trial, jurors heard from Porcari’s predecessor, Robert L. Flanagan, who was appointed by former governor Robert L. Ehrlich Jr. (R). Flanagan said Currie made a similar request of him for the same project in 2006 — with the same outcome.

Prosecutors have presented evidence they say shows Currie was seeking favorable treatment for Shoppers. The lawmaker on several occasions used a Senate letterhead to make requests to state officials for traffic lights and other issues on behalf of the grocery chain, for instance. And Currie invited state officials to meetings in his Senate suite about the chain’s businesses.

Defense lawyers have suggested Currie was merely being sloppy.

Much of the work Currie did for Shoppers affected stores outside his legislative district, prosecutors said.

Aris Melissaratos, a former state secretary of business and economic development, testified that Currie lobbied him for a $1.8 million grant to help a developer refurbish the Mondawmin Mall in Baltimore. The money, prosecutors have said, would affect the rent Shoppers paid at the site.

Melissaratos said he did not know about Currie’s connection to Shoppers but welcomed the senator’s interest. Bringing grocery stores to inner-city Baltimore was a priority for the Ehrlich administration, he said.

In other testimony, witnesses detailed what prosecutors say were questionable actions by Currie, the former chairman of the Senate Budget and Taxation Committee. In cross-examination, defense attorneys tried to put the episodes in a different light.

Once instance came with the testimony of Michael Richard, who was director of the Maryland Energy Administration under Ehrlich. In 2004, Richard said, he was weighing whether to delay the state’s implementation of new energy-efficiency standards for nine categories of commercial and household products — standards that could have meant expensive upgrades for businesses including Shoppers.

Under questioning by a prosecutor, Richard said he was “kind of excited” to hear from his staff that Currie expressed support for the delay in two categories: commercial refrigeration cabinets and large-scale air conditioners. “It seemed to represent that the senator had come around to our point of view,” he said.

Under cross-examination, Richard said that he had never spoken directly to Currie about this issue and that he wasn’t sure whether Currie made a “request” for a delay or merely expressed “concerns” about the timetable.

Richard said he heard from other senators and businesses concerned about the difficulty of meeting the standards under the timetable that was in place. Ehrlich, his boss, also supported the delay, he said.

Currie, Richard testified, “was requesting something that we were inclined to do.”