In Florida, G.O.P. Help for Unions

But now it looks as if the bill could falter before the legislative session ends next week. Unions representing teachers, firefighters, the police and other public employees say they have persuaded nearly half of the Senate’s Republicans to oppose the bill by reminding them that in Florida, far more than in most states, organized labor has supported Republicans.

“We have traditionally been a Republican-based organization,” said James Preston, president of the Florida Fraternal Order of Police. “How much more conservative can you get than the police officers? Who wants to go against the cops and firefighters on these matters?”

Still, the unions’ success is surprising, especially since Republican lawmakers in traditionally labor-friendly states like Wisconsin and Ohio have passed far tougher antiunion legislation this year. In Florida, just one in 20 of workers in the state belongs to a union.

By some counts, 12 of the 28 Republican senators are against the latest version of Mr. Thrasher’s bill, which would require public employee unions to get each member’s permission each year before they could use that person’s dues for political purposes. Senate Democrats are unified in opposition to the bill. Republican and business leaders — noting that Florida’s state employees contribute nothing toward their pensions — have praised Mr. Thrasher’s bill because it would reduce unions’ leverage over health coverage and pensions.

“These are government unions that are negotiating oftentimes against the taxpayers,” said Mark Wilson, president of the Florida Chamber of Commerce. “It’s not fair that the taxpayer-funded payroll system is collecting union dues that are used politically against the taxpayer.”

But Senator Miguel Diaz de la Portilla, a Republican representing Miami, said the bill was too punitive. “I don’t think it’s necessary legislation,” he said. “It doesn’t do anything to create jobs. It creates a lot of discord unnecessarily.”

He said the fact that unions in Florida were weak had forced them to be bipartisan. Using Wisconsin as an example, he said, “You just don’t have the animus between union and antiunion here that you have in some other places.”

Indeed, some of the bill’s Republican opponents have enjoyed labor’s campaign support and worked with unions on numerous issues.

Mr. Thrasher’s bill originally had two main provisions. In addition to requiring members’ permission for using dues money for politics, the legislation would have barred the state or any community from deducting union dues from workers’ paychecks and forwarding that money to unions.

Union lobbyists repeatedly said the bill would cripple the payroll deductions that fuel labor’s political efforts while continuing to allow similar deductions at 360 organizations and private companies, including insurers, that spend money on politics.

Unions also said they were being scapegoated for Florida’s budget problems. They argued that the recession and Wall Street, not union-negotiated pay and benefits, caused Florida’s $3.6 billion deficit.

Those arguments resonated with lawmakers.

Rene Garcia, a Republican senator who represents Hialeah, said he saw little need for the bill because Florida’s public employees were already not required to join the unions that represent them or to pay dues. “I don’t like this bill because it’s not fair when you single out one group,” he said.

Mr. Thrasher, former chairman of the Florida Republican Party, saw that he did not have the votes for his original legislation even though the House had already passed a similar bill. So he dropped the provision eliminating the dues check-off.

Mr. Thrasher did not respond to interview requests. But Senator Don Gaetz, a Republican from Destin, said the bill was revised to make clear that it did not intend to cripple unions.

“There’s no intent to stop unions from using funds for other very legitimate purposes,” he said. “The issue is, should the taxpayers of Florida be collecting money from public employees to be used by a union for direct partisan purposes? And the answer to that is no.”

Unions continue to fight the watered-down bill. “It could make unions in Florida a toothless tiger in politics,” said Rich Templin, chief lobbyist for the state A.F.L.-C.I.O.

In a sign that the bill is in trouble, Governor Rick Scott, a Republican, personally lobbied four Republican senators on Wednesday to back it, according to Mr. Diaz de la Portilla.

Gary Rainey, president of the Florida Professional Firefighters, said there was not enough Senate support to pass the bill in an up-or-down vote. But he feared that Republican leaders would secure passage by attaching it to another bill.

“It’s been a continuous battle shoring up support,” he said. “It’s not over until the fat lady sings.”