The Statehouse filled with as many as 10,000 demonstrators who chanted, sang the national anthem and beat drums for hours. The noise level in the Rotunda rose to the level of a chainsaw, and many Madison teachers joined the protest by calling in sick in such numbers that the district had to cancel classes.
The new Republican governor, Scott Walker, is seeking passage of the nation's most aggressive anti-union proposal, which was moving swiftly through the GOP-led Legislature.
If adopted, it would mark a dramatic shift for Wisconsin, which passed a comprehensive collective bargaining law in 1959 and was the birthplace of the national union representing all non-federal public employees.
As protesters chanted "Recall Walker now!" outside the governor's office door, the governor insisted he has the votes to pass the measure, which he says is needed to help balance a projected $3.6 billion budget shortfall and avoid widespread layoffs.
Walker said he appreciated the concerns of protesters, but taxpayers "need to be heard as well." He said he would not do anything to "fundamentally undermine the principles" of the bill.
"We're at a point of crisis," the governor said.
A budget committee was expected to consider the proposal later Wednesday. At one point during the protests, Republicans said they intended to offer substantive changes, but they soon revealed that all the core elements would remain.
Senate Major Leader Scott Fitzgerald said the bill would be modified to include an extension of grievance procedures for employees who lose bargaining rights. Other changes were to be revealed before the committee vote.
The full Legislature could begin voting on it as early as Thursday.
As the bill appeared ready to advance, tensions rose in the Capitol. Police roamed the halls, restricted access to some rooms and stood watch outside the governor's office.
In addition to eliminating collective bargaining rights, the legislation would also make public workers pay half the costs of their pensions and at least 12.6 percent of their health care coverage — increases that Walker calls "modest" compared to those in the private sector.
More than 13,000 protesters gathered at the Capitol on Tuesday for a 17-hour public hearing on the measure. Thousands more came Wednesday.
"I'm fighting for my home and my career," said Virginia Welle, a 30-year-old teacher at Chippewa Falls High School. She said she and her husband, who is also a teacher, each stand to lose $5,000 a year in higher pension and health care contributions.
Welle said she could never get that money back since the unions would be unable to bargain over benefits under Walker's plan.
The protests have been larger and more sustained than any in Madison in decades. Dozens of protesters spent the night in sleeping bags on the floor of the Rotunda. A noise monitor in the Rotunda registered 105 decibels at midday Wednesday — approximately the same volume as a power mower or chainsaw.
Beyond the Statehouse, more than 40 percent of the 2,600 union-covered teachers and school staff in Madison called in sick, forcing the superintendent to call off classes in the state's second-largest district. No other widespread sickouts were reported at any other school.
Prisons, which are staffed by unionized guards who would lose their bargaining rights under the plan, were operating without any unusual absences, according to a Department of Corrections spokeswoman.
Walker has said he would call out the National Guard to staff the prisons if necessary. A union leader for prison workers did not immediately return messages.