As state Sen. Ulysses Currie faces trial this week on federal corruption charges, his lawyer is expected to argue before a jury that the legislator's work on behalf of a grocery chain in Annapolis didn't constitute an illegal bribe but merely an ethical lapse.

"The difference is very subtle sometimes," the lawyer, Joseph Evans, said at a recent hearing. "It's hard to know sometimes what the difference is."

Currie, a Democrat and former chairman of a powerful Senate committee, is accused of accepting hundreds of thousands of dollars from Shoppers Food Warehouse over five years in exchange for securing meetings with top state officials and pushing favorable legislation for the company, headquartered in his Prince George's district.

While the trial could determine Currie's political future, it also could reveal how behind-the-scenes politicking and lobbying gets done in Annapolis. A number of Annapolis insiders are expected to take the stand, and Currie's defense plans to broadly argue that members of Maryland's citizen legislature often confront ethical quandaries because of their outside employment.

Judge Richard Bennett, who is presiding over the trial that's expected to last up to six weeks, said during a hearing last week that a handful of state lawmakers may take the stand as character witnesses for Currie. In addition, several well-known Annapolis lobbyists and legislative staff members are mentioned in court documents and also could be called.

Among the Annapolis power brokers mentioned in court documents are Gil Genn, a lobbyist who testified before the grand jury, and Timothy Maloney, a former Prince George's County delegate who prosecutors say helped Currie forge a deal at the heart of the case.

Former State Highway Administrator Neil Pederson, who oversaw the agency when Currie tried to expedite the installation of a stop light near a Shoppers grocery store in 2005, also figures prominently in the case.

Two former Shoppers executives, William White, who was the company's president, and R. Kevin Small, former vice president for real estate development, will be on trial with Currie as co-defendants.

And several Shoppers' employees are expected to testify. Shoppers' parent company entered a deal to pay a $2.5 million fine and cooperate with prosecutors in lieu of facing charges.

Evans has noted in pre-trial hearings that the part-time nature of the General Assembly creates "acute" problems for lawmakers in distinguishing when they are acting as public officials. About 80 percent of lawmakers hold outside employment, mostly as businesspeople or lawyers, Evans said.

The defense argues that lawmakers are allowed to "assist or represent" their employers with matters before state agencies as long as their help is "incidental" to the business and a "customary" part of the job description. Currie is being represented by the federal public defender's office.

Currie chaired the Budget and Taxation Committee, a panel that helps determine billions of dollars in state spending, for eight years until last year when he was indicted.

He is a close friend and ally to Senate President Thomas V. Mike Miller.

Prosecutors allege that within weeks of Miller elevating him to the chairmanship of the budget committee in November 2002, Currie offered to help Shoppers in exchange for monthly payments. They said Currie wrote to White, then-president of Shoppers, and offered "substantial assistance" with the company's "community relations and outreach efforts."

The letter was prepared with help from Maloney, who was Currie's lawyer at the time, according to court documents.

In December 2002, prosecutors said Currie asked for $5,000 a month. In February 2003, they said White replied and offered $3,000 a month. Prosecutors said that the two sides reached an agreement and that until the arrangement ended in 2008, Currie accepted payments from Shoppers totaling $245,816.

They said Currie tracked his work for Shoppers in a document titled "Accomplishments on Behalf of Shoppers," listing a dozen agency and legislative hurdles he helped the company overcome, according to the indictment.

The list includes securing road improvements near stores in Prince George's County and Baltimore County, and facilitating state approvals for the construction of a store in Chillum, according to court documents.

But Currie's defense contends the senator was hired as a consultant and was merely doing his job by helping them with meetings. His lawyers also are expected to raise Currie's health problems, possibly as a defense for allegedly giving false statements to FBI agents.