He has called it the largest and costliest public corruption investigation he has ever seen. "And there is no question it is at taxpayer expense," he said.

Maryland State Bar Association conduct rules prohibit criminal defense attorneys from charging their clients only if they are acquitted, but attorneys can greatly reduce their fees regardless of a trial's outcome.

Dana P. Moore, chairwoman of the city's ethics board and a private attorney, said it is "industry standard" for defense attorneys to cut high-profile clients huge fee breaks because of the public relations benefits they receive. She said she sees no ethics violation if that's what is happening in Dixon's case.

But other ethical red flags could be raised if Dixon ever reveals the structure of her legal fees.

Lobbyists and others who do business or have a financial interest with the city may not contribute to an elected official's legal defense, according to a city ethics board opinion issued in 2008. Ethics rules also require public officials to report gifts greater than $50 from those doing business with the city.

None of Dixon's attorneys in the case does business with the city.

However, a recent member of Weiner's firm, Frank Boston, lobbies the city on behalf of nearly a dozen high-profile clients.

Boston said he wrote a letter to the city ethics board to check whether Weiner's representation of Dixon would cause a conflict with his lobbying work. The ethics board replied with a list of questions that focused on what his work would be on the mayor's case. Instead of answering, Boston said, he felt it would be best to sever ties.

In February, a month after Dixon was indicted, Weiner and Boston formally separated their businesses, though Boston continues to work out of Weiner's office space in Clipper Mill.

"Lobbying the mayor and City Council of Baltimore and representing her in this matter would create a sense of impropriety, even if legally it was OK," Boston said. "Therefore, we decided it was in everyone's best interest that until the trial was over, I distance myself from the firm."

There are no state laws that specifically govern whether local elected officials can be reimbursed for their lawyers' bills. And there aren't local rules either - reimbursement is decided on a case-by-case basis by the city Board of Estimates, which Dixon controls.

Although Dixon would be within her rights to seek taxpayer help, there could be significant political costs, observers said, particularly at a time when the cash-strapped city is laying off employees and cutting services. She is up for re-election in 2011.

Former Baltimore Mayor Kurt L. Schmoke said the details from the trial will determine whether the public can stomach paying Dixon's legal bills.

"If the reaction of the public is these were meaningless charges, then there may be support for some kind of reimbursement of her expenses," Schmoke said. "If people think that she was acquitted on a technicality, and yet there was really some substance to this, then there would be less support."

Across the country, elected officials faced with criminal charges have relied on taxpayers and their own campaign funds to pay their sometimes enormous legal bills.

Attorneys for former Memphis Mayor Willie Herenton, facing possible federal indictment, billed him $55,000, the local newspaper reported, charges that were passed along to taxpayers. The former Birmingham, Ala., mayor, who was convicted last month of bribery, was declared indigent by a judge, meaning taxpayers are on the hook for at least $60,000 in lawyer fees.

Former Illinois Gov. Rod R. Blagojevich, who ran up more than $2 million in lawyer fees in his federal public corruption case, and former Detroit Mayor Kwame Kilpatrick, who incurred more than $1 million in legal costs during his obstruction of justice case and civil suits, both tapped campaign funds.

But Maryland's laws are clear: An elected official can use campaign funds only for expenses that advance a campaign or promote a candidate.

A 1993 opinion by then-Attorney General J. Joseph Curran Jr. and reaffirmed last year by Attorney General Douglas F. Gansler rules out using the money to pay for criminal defense unless the case involves campaign finance violations.

None of the charges against Dixon fits that category.

Another indicted Baltimore elected official could make the case that her legal expenses should be paid out of her campaign coffers, said Jared DeMarinis, director of candidacy and campaign finance at the Maryland State Board of Elections. Councilwoman Helen L. Holton is accused of improperly requesting that two developers pay for a $12,500 political poll. She is charged with campaign finance violations.

Baltimore Sun reporter Annie Linskey contributed to this article.