ATLANTA — A dozen state lawmakers who recently promised to cap lobbyist spending ahead of election season did not publicly back those limits during this year’s legislative session.

The new list of supporters, which includes high-ranking Senate leaders, comes just before politicians head into the July 31 primary election and, in one case, face possible discipline for violating ethics rules. A coalition of tea party, conservative and open government groups are pushing to make the lobbying cap an issue in the campaign.

By signing the pledge, General Assembly candidates commit to co-sponsoring legislation that would ban lobbyists from giving public officials gifts worth more than $100. Lobbyists can currently spend as much as they want so long as they publicly report their spending.

Eleven incumbents seeking office again have signed the pledge but did not sign on as co-sponsors of bills to cap lobbyist spending. Another incumbent who signed the pledge but declined to co-sponsor the bill is stepping down. The list of incumbents who didn’t lend their name to the measure includes Senate President Pro Tempore Tommie Williams, Senate Majority Leader Chip Rogers and Sen. Don Balfour, chairman of the powerful Rules Committee. Those men have considerable influence over what bills go forward.

For example, Balfour chairs the committee where the Senate bill capping lobbyist spending was assigned before the measure failed. He and Rogers face Republican opponents who have signed the pledge. Balfour, who did not return a message seeking comment, also faces a probe by the Senate Ethics Committee into allegations that he improperly sought reimbursement for conducting official state business on days he was far from the Statehouse or traveling out of state with lobbyists.

“I take every member of the General Assembly and certainly my Senate colleagues at their word,” said Sen. Joshua McKoon, who sponsored the Senate proposal to set a cap. “Someone signs a pledge in front of the public at large and commits themselves to a position, I certainly expect they’re going to honor that when they go back.”

Williams, who recently decided to step down as president pro tempore, did not co-sponsor the bill because he believed lawmakers needed more time to study it, said his legal counsel, Gerald Huang. The cap was one part of a bill that also set limits on how much lobbyists could spend to subsidize travel by public officials, kicked people with lobbying ties off the state’s ethics commission and increased other financial disclosure requirements.