A bill intended to give local officials a pass on costly ethics fines has morphed into one that will allow state lawmakers to protect incumbents from primary challengers and discourage third-party groups such as Americans for Tax Reform from launching campaign attacks.

Senate Bill 127, which passed the House Tuesday by an overwhelming and bipartisan margin, would require issue advocacy organizations that get involved in elections in Georgia to file disclosures saying how much they spent on the effort and where they got their money. Backers say the provision will bring more transparency, but at least one expert said it could prompt lawsuits claiming an infringement of First Amendment rights.

The proposed disclosure requirement could discourage groups like Washington-based Americans for Tax Reform to get involved in local races. That's important to many in the General Assembly who signed the group's pledge never to raise taxes but have supported House Bill 170, the administration's omnibus transportation plan.

Americans for Tax Reform, best identified by its founder Grover Norquist, has labeled the transportation bill as a tax increase. The group already warned legislators that a vote for the bill would be considered a violation of the pledge.

Norquist told The Atlanta Journal-Constitution that lawmakers must be “ashamed” of their votes on the transportation bill if they are seeking to silence him.

“It is interesting that the Georgia House passed this legislation the same week they passed a giant tax increase,” he said. “Not only do these politicians want to raise taxes, they want to prevent anyone from pointing out to their voters that they raised taxes.”

Atlanta lobbyist Trip Martin, who represents corporations in favor of the transportation plan, filed a complaint against Americans for Tax Reform with the state ethics commission, alleging Norquist should be required to register as a lobbyist. In an op-ed for The Daily Caller, the group's state affairs manager accused House Speaker David Ralston, R-Blue Ridge, of conspiring to bring the complaint.

Former ethics commission director Rick Thompson, now a consultant for politicians and campaign committees, said he thinks the provision may not really result in more disclosure. But he said it likely will spawn lawsuits as organizations challenge it as an infringement on their First Amendment rights.

“I absolutely think that there will be some kind of challenge to it,” he said.

Another item tucked into the House version of the bill changes campaign finance rules to allow a party caucus — a faction of legislators drawn from the House or the Senate and affiliated with a particular party — to make unlimited donations to a party ticket or group of candidates.

In primaries, the political parties generally avoid supporting or opposing a candidate from their own party. The House proposal would permit party caucuses to do that instead.

Rep. John Pezold, R-Fortson, one of a handful of young, recently elected lawmakers to oppose the bill, said it is needless protection for incumbents who already have a head start.

“I’m an incumbent now and I’m certain I may benefit from it,” he said. But, he said, “I (challenged) an incumbent (in a primary) and won. When you do that you are behind the eight ball in terms of money and momentum. The odds already are skewed heavily to the incumbent.”

The House version of the bill is dramatically different from how it passed the Senate and a conference committee will have to work out the differences quick if it is to pass. Thursday is the 40th and final day of the legislative session.

The Senate version dealt exclusively with providing a way for local officials to escape fines handed down by the ethics commission during a four-year period when candidates for city and county offices had to file campaign disclosures electronically with the state. The Georgia Municipal Association sought the legislation, arguing that years of chaotic leadership at the ethics commission, combined with the state’s defective computer system, had unfairly assessed late fees to some officials who tried to file on time.