Public sector unions in Iowa will have less authority to negotiate working conditions for teachers, nurses and correctional workers under a bill passed Thursday in the new Republican-controlled Legislature that critics say is aimed at crippling organized labor in the state.

The legislation, expected to be signed into law by Iowa's conservative governor, will prohibit workers from collectively negotiating over health insurance, extra pay and several other items currently covered by law. It's expected to be one of the most significant bills of the legislative session, in part because of loud opposition from Democrats and unions.

"We did not start this fight," said Ken Sagar, president of the Iowa Federation of Labor, AFL-CIO, after the chambers debated the legislation simultaneously and passed roughly an hour apart. "But we will not give up on this fight for the rights and lives of working Iowans."

Republicans have repeatedly denied claims that politics were involved in the legislation. Critics point to the fact that the minority party and labor groups were kept in the dark about the bill's drafting. It was then made public on Feb. 7, before it was fast-tracked through committee votes over a few days.

On Thursday morning, following days of on-and-off debate, Republicans used a rare procedural move in both chambers to force floor votes despite dozens of pending filibuster challenges from Democrats.

"The biggest losers today are the people of Iowa, who have been silenced by this process in what is really an unprecedented maneuver," said Democratic Sen. Joe Bolkcom, who spoke during a marathon debate in the state Senate that began Wednesday morning and continued into the night before a 29-21 floor vote.

The proposal is similar to Wisconsin's 2011 collective bargaining law that drew large demonstrations in that state. In Iowa, hundreds of people turned out at weekend forums to oppose the bill, which culminated with a large gathering Monday night at the Iowa Capitol. But the building has been relatively empty since then, a stark contrast to the turnout in Wisconsin that made national headlines.

Since the collective bargaining law went into effect in Wisconsin, membership for both public and private unions in the state has dropped 40 percent.

Republicans have repeatedly said the bill will give local governments more flexibility with their budgets and promote talented employees.

Just before the 53-47 House vote, GOP Rep. Steven Holt said Republicans called the bill "a win" that would provide greater accountability for all collective bargaining parties.

"We inadvertently created a system that discourages innovation and instead simply protects the status quo," he said, referencing the 1974 collective bargaining law that was passed by a Republican governor to avoid employee strikes.

Union organizers argue the current law works and ensures employers have a fair seat at the table alongside workers. The Iowa State Education Association, which represents 34,000 Iowa school employees, said the system works so well that more than 160 school districts had settled bargaining contracts in the past week in a rush to avoid complications from the bill.

One of those complications may be a legal challenge. Danny Homan, president of the American Federation of State, County and Municipal Employees Iowa Council 61, said Thursday that his organization would file a lawsuit soon to challenge the bill's constitutionality.

There are roughly 180,000 public sector employees in Iowa that are covered by union contracts and would be impacted by the legislation. Public safety workers, such as enforcement officers and firefighters, would be exempt from some provisions of the bill.

Those public safety workers would still be subject to a requirement that unions manually collect dues and that they hold more frequent elections on whether to dismantle. Legal experts who study labor issues say the move is aimed at financially crippling unions. Academics say the ripple effect is weakened unions with reduced membership, less financial stability and a smaller voice in state politics.

Two of the largest public sector unions in Iowa contributed a combined total of more than $1 million to the Iowa Democratic Party in 2016, a figure that is based on available campaign contribution filings.