Asking politicians to pass legislation that would restrict contributions to their campaigns has to be one of the most quixotic ventures in this political town. But Ricki G. Wadsworth, the lobbyist here for the 7,000-member Maryland Common Cause, makes her living at it.

She had a victory of sorts late last week when, for the first time in years, the House of Delegates actually debated a proposal to limit campaign contributions by political action committees.

Despite Wadsworth's best efforts, the outcome was inevitable, House members said; after several delegates verbally savaged the PACs bill, the electronic tally board in the chamber exploded in a haze of 81 red "no" votes.

"Oh my God," murmured Wadsworth, who was watching from a visitors gallery. Later she described the bill as "brilliantly drafted but, politically, a disaster."

It was not the first defeat that Maryland's male-dominated legislature, an often sluggish machine lubricated by expense-account goodies, has handed Wadsworth, who is one of the few female lobbyists in Annapolis and one with no expense account to bestow favors. Her $21,690 salary pales next to those of her antagonists from the state's banking, real estate and medical establishments, some of whom have six-figure salaries for 90 days of work.

Remarkably, however, Wadsworth seems to relish a job that is designed for frustration and burnout. Moreover, after three years here, she finally has achieved some measure of acceptance and success in circles where "good government" types are regarded with suspicion or outright hostility.

"I respect her, even though we're on completely opposite sides of the spectrum," said Ed Hilley, who has lobbied here for 17 years for Maryland's real estate industry.

Hilley, who squared off against Wadsworth in hearings on the PAC limitation bill, said his frequent foe has the crucial character trait that separates effective advocates from those who legislators ignore.

"She has credibility," Hilley said. "That means you're not puffing before a committee and you give a straight answer, even if it hurts. Ricki is credible."

Wadsworth belongs to a small cadre of public interest lobbyists in Annapolis who, with part-time secretaries or no staff at all, promote issues that politicians love to embrace publicly -- a cleaner and safer environment, laws encouraging fair electoral campaigns, programs to aid the disadvantaged -- but kill when it comes to a vote.

The task of public interest lobbyists is identical to that of the industry representatives they so frequently battle: merely to persuade a constitutional majority of the House and Senate to pass or kill a particular piece of legislation, then persuade the governor to sign or veto legislation that has passed.

What separates the Wadsworths of Annapolis from highly paid and well-financed lobbyists are tactics. Where Wadsworth relies on herself and telephone calls and post cards to legislators from Common Cause members, her opponents may use the persuasive power of a public relations agency, a phalanx of aides or the promise of campaign contributions to make their case.

"They spend time wining and dining legislators; I get my members to call or write," said Jim Clarke, who will earn $5,600 this session lobbying for the Sierra Club.

Clarke, a frequent Wadsworth ally, added: "I think I make a difference. They have influence. I have some, too. If I didn't think so, I wouldn't be here."

Wadsworth believes that she exerts some influence, although she has had to overcome some entrenched sexism to do it, she said.

"There are legislators who have had a hard time taking me seriously," said Wadsworth, recalling one hearing where an Eastern Shore senator praised Common Cause for hiring a "prettier" class of lobbyist.

Mostly, Wadsworth has had to demolish "the caricature that we're screaming public do-gooders who can't get along. There are still people who feel Common Cause is the white-horse lobby."

But Maryland Common Cause almost certainly was that in the mid-1970s, when the public interest lobby first arrived in Annapolis, according to several legislators and public interest lobbyists.

During that Watergate era, when Maryland's political foundation was rocked by scandals, Maryland Common Cause rode the wave of public resentment against dirty politics. The group boasted 12,000 members and scored an impressive string of legislative victories, including passage of a strong financial disclosure law, a comprehensive ethics bill, a "fair campaign" finance measure and a "sunset" law that requires certain agencies to justify their existence or face extinction.

Today, however, "Our job is a good deal harder," said Joseph M. Hogan, a Bethesda resident who ran Maryland Common Cause in 1974 and 1975. "It's not that the issues are less important, but they're a little less compelling because people may not remember Spiro Agnew," a reference to the former vice president who was forced to resign after allegations of political payoffs while he was Maryland's governor.

"The channels to state officials are kind of clogged by special interests," Hogan added. "There's a lot more competition for their attention."

To get the attention of 188 delegates and senators, Wadsworth has resorted to techniques both effective and controversial: a system of newsletters, post card "alerts" and telephone campaigns that she described as "our counterpart to hitting them over the head with a two-by-four."

For instance, Wadsworth infuriated Sen. Sidney Kramer (D-Montgomery) early in the session when she mailed post cards to Common Cause members in Kramer's Silver Spring district suggesting that the senator had backed down from a promise to support limits on PAC contributions.

Kramer, who generally shies away from committing himself early on controversial legislation, denied making the promise and gave Wadsworth a piece of his mind after hearing from many angry constituents. More than 2,000 Maryland Common Cause members live in Montgomery County, where Kramer plans to run for county executive next year.

"I indicated to her she had misstated the facts of a year ago," said Kramer. "An organization like Common Cause has to be clear, proper and accurate. My image of Ricki has been tarnished."

Wadsworth stands by her Kramer "alert" -- she has sent out half a dozen on other legislators this session -- and defends the inexpensive lobbying technique as a service to her members and a proper prod for politicians here.

"It's not so much we're applying pressure as it is sheer communication," Wadsworth said. "Unless they feel there's a substantial interest in an issue, they won't listen to you."