Tens of thousands of demonstrators again descended on the state Capitol in Wisconsin Saturday in opposition to Gov. Scott Walker's plan to dramatically curb collective bargaining for public employees in the state.

The protests, which followed massive demonstrations the past two weekends, came one day after Walker notified unions that he would lay off as many as 1,500 state workers next month - jobs that he said could be saved if his plan were enacted.

Filmmaker Michael Moore was among those who took part in the demonstrations, which have drawn throngs of rank-and-file union members and supporters vehemently opposed to Walker's plan.

"These protests are going to go on until Scott Walker comes to his senses," said Graeme Zielinski, a spokesman for the Wisconsin Democratic Party.

As the crowd rallied at the Capitol, Democratic Party volunteers canvassed the districts of eight Republican state senators with petitions that, if enough people sign them, could force recall elections. The goal is to replace senators who support Walker, or at least pressure them into compromise.

Under Walker's plan, most Wisconsin government workers - other than police or firefighters - would be forbidden from bargaining for retirement and health-care benefits and for wage increases beyond the rate of inflation.

The measure would also prevent unions from collecting dues through payroll deductions. Walker's plan would also stop unions from requiring members to pay dues, and it would require annual votes to recertify unions.

The bill would require state workers to pay more as well for their health care and pensions, which would amount to an 8 percent reduction in take-home pay. Labor leaders have agreed to those concessions, but they oppose the curbs on collective bargaining and other changes that they say would be fatal to the state's public-sector unions.

Walker's bill has already passed the state Assembly, but 14 Senate Democrats fled the state to prevent that body from forming a quorum that could pass the legislation. The Democratic lawmakers say that back-channel negotiations with Walker and Senate Republicans have so far not yielded a compromise.

Walker says his plan is needed to ease a deficit that is projected to reach$137 million in the current year and $3.6 billion over the next two years. He has said that the gaps must be close without state - or local - tax increases and that curbing collective bargaining would give local leaders the tools they need to reduce worker salaries and close the deficits.