Both houses of the GOP-controlled Legislature convened shortly before noon amid noisy protests outside the state Capitol that began more than a week ago in an epic showdown that is being watched nervously by organized labor across the country.
The Senate was unable to take up the union measure because its 14 Democrats skipped town last week, denying the chamber a quorum. But Assembly Speaker Jeff Fitzgerald pledged that his chamber would approve the bill this week, despite the blizzard of Democratic amendments.
Turning up the pressure on the Democrats, Gov. Scott Walker warned that state employees could start receiving layoff notices as early as next week if the bill isn't passed soon. The layoffs couldn't take effect immediately - existing union contracts could forestall them for weeks or months - and Walker wouldn't say which jobs he would go after first.
"Hopefully we don't get to that point," the governor said in a statement.
Borrowing the strategy pioneered by President Franklin D. Roosevelt, Walker took his case straight to the voters Tuesday evening with a speech from his Capitol office that he called a "fireside chat." With protesters drowning out his message as it was played over monitors in the rotunda, Walker calmly laid out his case for the bill, saying it was needed to balance the state's budget now and into the future.
"It certainly isn't a battle with unions," Walker said. "If it was, we would have eliminated collective bargaining entirely or we would have gone after the private-sector unions."
Walker warned of "dire consequences" if the Democrats don't return soon to pass the bill, saying up to 1,500 state workers could be laid off by July with another 6,000 forced out of work over the next two years.
One of the missing Democrats, Minority Leader Mark Miller, delivered his own response from Illinois.
"The only action available to us to slow this down and allow democracy to work was to take us out of the Capitol," he said.
While Wisconsin remained the main front in the national debate over union rights, similar battles were taking shape in other states. In Indiana, House Democrats walked out of the Statehouse on Tuesday, blocking a GOP-backed bill against mandatory union dues. Only three of the 40 Democratic members of the chamber were present, depriving it of a quorum.
A similar debate in Ohio drew thousands of union protesters Tuesday, prompting officials there to lock the doors to the Statehouse.
In Wisconsin, if lawmakers take no action on the union bill by the end of the week, the state will not be able to refinance debt that Walker had counted on for $165 million worth of savings under the legislation. Republican leaders in both the Senate and Assembly said they have the votes to pass the bill.
Fitzgerald said the bill was a key part of the Republican agenda to cut government spending that won the GOP majorities in the Legislature in November.
"When you talk about a compromise, no. We're going to make a reform," the Assembly speaker said.
Debate began in the Assembly with the Democrats introducing amendments that would do such things as restore public employees' right to strike and submit the bill to a referendum before it could take effect. Given the number of amendments Democrats were proposing, an actual vote on the measure may not happen until Wednesday or later.
"It's going to be a long day," Democratic Minority Leader Peter Barca said at the start of debate. "Tempers are going to flare."
He was right. Two Democrats lashed out at Republican lawmakers and aides for laughing at them during the debate.
"This is not a game! We're dealing with people's lives! This isn't funny!" Rep. Andy Jorgensen shouted in the chamber, his face red. "I haven't laughed in a long time, especially not on a day like this!"
Rep. Cory Mason, a former organizer for the American Federation of Teachers, said Wisconsin has enjoyed more than 50 years of labor peace between state and local public employees and their bosses after passing collective bargaining rights in 1959.
"What the governor is proposing and what the majority is proposing today is to break that labor peace," he said.
The roar of protesters in the Capitol rotunda, many of whom were banging on drums and chanting through megaphones, could be heard while both the Senate and Assembly met.
The Wisconsin bill would force state and local public workers to contribute more toward their pensions and health care and would strip them of the right to negotiate benefits and working conditions. They would largely be limited to negotiating pay raises no greater than the inflation rate.
The proposal, designed to help Wisconsin plug a projected $3.6 billion hole in the budget, has led to eight straight days of monumental protests that grew as large as 68,000 people on Saturday.
The Senate was stymied for a second time in its attempts to take up the bill after none of the 14 Democrats who skipped town on Thursday showed up. Under Senate rules, 20 lawmakers must be present to take up a budget bill. There are only 19 Republicans.
Unable to act on Walker's proposal, the remaining Republicans instead took up some non-controversial measures, voting to extend tax breaks to dairy farmers and unanimously commending the Green Bay Packers on winning the Super Bowl.
Unlike last Thursday, when the Senate galleries were filled with protesters who disrupted action by shouting, only about a dozen people showed up under heavier security to watch the action on Tuesday.
In the Assembly, the gallery was packed with hundreds of spectators who watched the debate without causing any disruption. Democrats wore orange shirts to show solidarity with protesters that read, "Fighting for working families." Thousands more people watched the debate on TV monitors inside the rotunda.
Walker and Republican leaders have repeatedly called on the Senate Democrats, who fled to Illinois, to return and get back to work. Democrats have said they won't come back until Walker is willing to negotiate.
"We'd love to come back today," said Sen. Jon Erpenbach. "We could be up there this afternoon and pass this if he would agree to removing the language that has absolutely nothing to do with balancing the budget."
Packers star Charles Woodson and two other players, along with five former team members, have come out against the bill.
Associated Press writer Ryan J. Foley contributed to this report.