Pittsburgh Councilman William Peduto has often railed against what he terms "pay to play" politics, but freely admits that on Thursday some who play with city government will pay into his campaign.

Among those expected to attend his fundraiser are representatives of developers, landlords and law firms that frequently interact with city government, and the event will be held at Bobby Rahal Mercedes-Benz, a dealership that benefited from his mediation of a zoning dispute in 2006.

Any contradiction between his platform and his politics is a result, Mr. Peduto said last week, of his need to compete on a playing field in which there are virtually no campaign finance rules. "It's kind of hard to campaign with one arm tied behind your back when others don't follow those rules."

There are cities with rules barring those who get money from government from giving money to campaigns. But in Pittsburgh politics, more than half of the top 100 campaign donors have economic relationships with the city -- contracts, development deals, collective bargaining or special permits -- a Post-Gazette analysis published yesterday found.

That finding "speaks very highly of why government contracting reform needs to be in place," said Craig Holman, a national expert on contracting reform and the governmental affairs lobbyist for Public Citizen, a Washington, D.C.-based good government group. "If lawmakers are relying on campaign contributions from those who are getting government contracts, there is a very high danger of corruption."

Six of Mayor Luke Ravenstahl's top 10 contributors from 2005 through 2007 have had recent business dealings with the city. He has said that campaign checks don't affect government.

"It doesn't, not in my mind," he said. "I know that's been the discussion of late. But the reality is the system is one that allows people to voice their support for a candidate by making financial contributions.

"For them to write checks and support us I think shows that there is a united front both in the corporate community and in the neighborhoods that wants to see our administration continue, and I'm honored to have that support."

New Jersey was wracked with scandals over contracts and contributions, Mr. Holman said, and activists countered by pushing for state, city and municipal laws to eliminate any possibility that political donations would influence contracting. The state enacted reforms, and a group called Citizens' Campaign has successfully pushed for 65 strict local ordinances.

Jersey City, for example, recently enacted rules barring anyone who donated more than $300 to a campaign or $500 to a political action committee, or PAC, from getting any no-bid contract in the year after the contribution. It specifically applies to contracts for banking, insurance, consulting, public relations and management services granted by any part of city government.

In Pittsburgh, contractors freely give while chasing professional services contracts, which are not subject to lowest-responsible-bidder rules.

For instance, executives at South Carolina-based engineering and planning firm Wilbur Smith Associates gave Mr. Ravenstahl's campaign two $1,000 contributions, the first on Jan. 16, 2007, and the second on Jan. 25, 2007. On Feb. 1, they submitted a proposal to the city's Urban Redevelopment Authority to manage work on the Pittsburgh Technology Center site.

On April 16 and 18 of 2007, six firm members made contributions to Mr. Ravenstahl's campaign totaling $4,500. Two weeks later, on May 1, the contract was finalized, for as much as $450,000.

Wilbur Smith then got a contract with the URA for as much as $65,000 on Aug. 29, 2007, to help manage a Central Northside project. A firm executive made another $500 contribution on Oct. 4, 2007. On Oct. 25, the firm got another URA contract for no more than $400,000 to help design public improvements in the Oak Hill area of the Hill District.

One Wilbur Smith employee declined to answer questions Friday, and two others could not be reached for comment.

Mr. Holman said effective bans on pay-to-play politics bar businesses whose top executives or PACs have given recent, sizable contributions from seeking no-bid contracts. They prohibit any contributions during the negotiation and term of such contracts. They require that firms applying for such contracts disclose their political giving. And they allow donors to ask candidates to demand their contributions back if they want to clean their slate and compete for a contract.

Pittsburgh Councilman Patrick Dowd is on a panel created by Mr. Ravenstahl to improve city contracting procedures. The panel "absolutely needs to explore this question," of whether contributions by contractors should be limited, Mr. Dowd said Friday.

He said the panel will hire a consultant to advise it on practices in other cities, and to review policies on what contractors can and can't give to officials.

The states of New Jersey, Ohio and Connecticut have strong laws governing contributions by contractors, said Mr. Holman. Outside of New Jersey, so do a few cities -- Philadelphia, San Francisco and Los Angeles primary among them.

San Francisco voters in June barred officials who have any say over a contract worth more than $50,000 from accepting any campaign contributions from those who seek, or get, those contracts.

Campaigns are expensive, and Mr. Holman said rules like those taking hold in New Jersey cities do eliminate some donors. They don't seem to have stifled the electoral process, he said.

"In New Jersey, they're still spending a great deal of money on campaigns," he said. They're just not generating as many scandals, he added.