Republicans who reign over Burlington County collect bundles of campaign cash from firms that hold contracts with the Burlington County Bridge Commission.

So when a bill that unanimously passed the New Jersey Assembly State Government Committee last month called for restricting public vendors at "county bridge commissions" - there are only two in New Jersey - from donating to candidates, it was in effect a move to shut off the fund-raising spigot of the local GOP.

The architect? Burlington County Democrat Herb Conaway, who has coasted to re-election term after term in the Assembly's Seventh Legislative District but is looking at a tougher-than-usual race after new census numbers led to a change in district boundaries this year.

Some question Conaway's motives and timing, but he says the measure aims to bring accountability to the independent agency.

Bridge Commission spokeswoman Liz Verna asked: "Why would they single out the Bridge Commission among all the different authorities in the state?"

The answer has as much to do with underdog Democrats tussling with powerful Republicans in Burlington County as it does with the broader debate about curbing the exchange of contracts and election donations at the hundreds of local governing entities that have no strong rules against the practice.

Restrictions on pay-to-play have been in place at the state level since 2004. Yet a vast network of towns, counties, and independent authorities was exempted. Local entities are required only to advertise professional-services contracts through a "fair and open" process. They need not pick the lowest bidder and can - and often do - award contracts to campaign donors.

A proposal to close that loophole at the local level, announced in September by Gov. Christie, a Republican, is going nowhere in the Democratic-controlled Legislature.

Sen. Loretta Weinberg (D., Bergen) sponsored a bill similar to Christie's proposal in December, but it has not gotten traction because Republicans want the legislation to be expanded to cover contributions from labor unions.

"The way to do this would be a broad bill that affects every level of government and avoids the confusion of having a myriad of pay-to-play bills that [target] autonomous authorities, the state, the county, the municipalities, the sewer authorities, the bridge commissions," Weinberg said. "If everybody does their own, first of all, it's extremely confusing."

The lack of movement on pay-to-play favors legislative incumbents entering an election season in which all 120 seats are up for grabs, not to mention all the candidates for scores of local offices.

Asked why his bill was not broader, Conaway responded: "Not every bill does everything under the sun."

The Burlington County Bridge Commission is funded by the $2 tolls to cross into Northeast Philadelphia and Bucks County. Its commissioners are appointed by the Burlington County Board of Freeholders, which Republicans control, 4-1.

Conaway said the proposal had been in the works for a while and came in response to several scandals at the commission. The most recent was an episode in which a commission lobbyist pleaded guilty to overbilling the agency, and said in 2008 that he had been directed to kick back some of the money to the county GOP as a condition of keeping his contract.

"When people pay those tolls, they want those tolls to go to maintaining that bridge; they want the costs associated with that to be as low as they can be. And when political contributions are given . . . then we all see that as taxpayers, in the forms of higher cost for services that those folks provide," said Conaway, a lawmaker since 1998.

His legislation more broadly favors local Democrats, who in recent years have been disorganized and lacked funding. Proposed restrictions would apply to incumbents - who are often Republican - and would not touch some of the sources of Democrats' campaign cash, which tend to be unions and companies outside the county.

The legislation would ban firms that hold contracts of more than $17,500 at bridge commissions from making campaign contributions to local candidates in that county if they were serving in elected office when the agreement was awarded. Contractors would be banned from contributing to political party committees in that county.

The measure also would prohibit a bridge commission from entering into a contract of more than $17,500 if the contractor had made such a contribution during the previous 18 months.

An Inquirer report last year found that seven of the 10 professional-services firms that received the most money from the commission had donated more than $600,000 to Republicans in Burlington County during the last three years. Agency officials have insisted that there is no tie between contracts and donations.

The bill's second sponsor is Democrat Jack Conners, the Seventh District's other Assemblyman, who is not running for reelection after the once-a-decade redistricting knocked his hometown of Pennsauken into another district.

The candidate Democrats have recruited to replace him is Troy Singleton, a Burlington County bridge commissioner and the lone Democrat on the three-member panel, which is required to have one person from the minority party.

The more Democratic Seventh District, which spans the river towns, has largely been the exception to a Republican-leaning county. But both of Burlington County's party chairmen agree that the new legislative map has made the district more competitive. Heavily Democratic Pennsauken and Maple Shade were shifted out of that district, and Republican-friendly Mount Laurel and Moorestown were added.

Democrats also will have a more formidable opponent in Joseph Malone, a Republican Assemblyman from Bordentown who was moved from the 30th District into the Seventh. The 18-year veteran of the Legislature is running with Christopher Halgas, an executive at RCH Cable.

Singleton, who works for the carpenters union and could not be reached for comment, has $127,625 in his campaign chest, mostly from unions, lobbying groups and legislators. Conaway, a doctor, has $59,610 in campaign donations, much of it from the health-care industry.

Malone's campaign account has a balance of $168,917, including donations from Bridge Commission vendors. But he's no fan of pay-to-play restrictions.

If people are stupid enough to get involved in corruption, he said, "they're going to do it, no matter what we do in legislation."

His verdict: "It's just a tired old political nonsense bill."

Contact staff writer Maya Rao at 609-989-8990 or mrao@phillynews.com.