Madison, Wisconsin (CNN) -- Protesters, Tea Partiers and now rock 'n rollers.

Wisconsin's growing demonstration over a budget bill that supporters call vital and opponents label union-busting continues Monday with guitarist Tom Morello of Rage Against the Machine fame planning to play for the protesters a day after Republican Gov. Scott Walker signaled no retreat on the measure.

The growing crowds gathering daily in Madison, the state capital, over the issue exceeded 50,000 on Saturday, according to an official estimate, and shows no sign of abating.

"History is happening in the streets of Madison, Wisconsin and I'm going to be there," said a statement by Morello, who will perform in his solo identity as The Nightwatchman.

Calling the proposed budget law "unjust," Morello said he will join "teachers, students, firefighters, policemen, Green Bay Packers, nurses, steel workers, construction workers and religious groups that are filling the streets to protest."

He referred to Walker as "the Mubarak of the Midwest" in reference to the Egyptian leader ousted by popular protest, and accused the governor and unnamed corporate allies of trying to "rob American workers of their fundamental rights."

The Budget Repair Bill proposed by Walker to address a $137 million shortfall through June 30 would increase contributions of state workers for their pensions and health insurance benefits. It also requires collective bargaining units to conduct annual votes to maintain certification, a costly procedure, and eliminates the right of unions to have dues deducted from worker paychecks.

Last week, 14 Democratic state senators essentially boycotted the legislature and went to Illinois to prevent a quorum from passing the bill. The measure's opponents say they won't allow a vote unless Walker negotiates on the plan to eliminate collective bargaining rights for everything but wages.

Walker rejected such a deal Sunday in an interview on "FOX News Sunday."

He called the Democratic complaint of union-busting "a red herring" and said significant changes were needed for budgetary reasons, but powerful public employee unions were able to block the necessary adjustments.

"If we're going to ask our state and local workers who are doing a great job to pay a little bit more, to sacrifice, to help to balance this budget, we should also give them the flexibility saying that for those members, for those workers, who don't want to be a part of the union, if you don't want that deduction each month out of the paycheck, they should be able to get that $500, $600 or in some cases, $1,000 back that they can apply for their health care and their pension contribution," Walker said.

Democratic U.S. Sen. Dick Durbin of neighboring Illinois disagreed, saying that anyone who thinks the bill is only about money and the budget would also think that the Rev. Martin Luther King Jr. was working only for African Americans to have access to restaurants.

"There's a much bigger issue at stake here," Durbin said on the NBC program "Meet the Press," adding that Walker "is not setting out just to fix a budget; he's setting out to break a union."

However, Republican Rep. Paul Ryan of Wisconsin said the events in his state are a microcosm of the budget pressure felt by governors throughout the country .

"It just shows the point, all levels of government have been making empty promises to people," Ryan said on the CBS program "Face the Nation." "And these governors are telling people the truth."

Walker said he hoped the Democratic state senators would return to Madison so that debate on the bill could ensue, but added that all options were on the table -- including a possible contempt proceeding -- if they don't.

On Saturday, Tea Party activists supporting the bill brought a new dimension to the street demonstration. "Wisconsin is ground zero," said Tim Phillips, president of Americans for Prosperity. "I think it is going to determine largely whether the pampered nature of these public employees is finally reigned in."

One of the missing Democratic state senators, Jon Erpenbach, said all state and local public employees -- including teachers -- have agreed to the financial aspects of Walker's requested concessions on paying more for employee health care and pensions.

"In return they ask only that the provisions that deny their right to collectively bargain are removed," Erpenbach said. "This will solve the budget challenge."

Walker, however, said it was necessary to change the collective bargaining rules because the alternative would be laying off thousands of state employees.

"I can't have anybody laid off," he said on FOX. "I don't want a single person laid off in the public nor in the private sector, and that's why this is a much better alternative than to losing jobs."

Until Saturday's counter-demonstrators appeared, the growing protests since Monday were largely made up of those against Walker's plan. They remained the clear majority of those marching, with of them on Saturday drawn by the arrival of Walker's supporters.

There were no reports of major incidents or arrests by late Saturday afternoon, and authorities expressed their gratitude.

"On behalf of all the law enforcement agencies that helped keep the peace on the Capitol Square Saturday, a very sincere thank you to all of those who showed up to exercise their First Amendment rights," Madison police said in a statement. "You conducted yourselves with great decorum and civility, and if the eyes of the nation were upon Wisconsin, then you have shown how democracy can flourish even amongst those who passionately disagree."

White House Press Secretary Jay Carney addressed the continued protests Friday, saying President Barack Obama "is very understanding of the need for state governments, governors, state legislatures to reduce spending to make tough choices to be fiscally responsible."

But he added, "He also feels very strongly that we need not to make this an assault on the collective bargaining rights of workers in any given state.

"He understands public employees need to make sacrifices just like everyone else."

Walker and other Republicans criticized Obama on Sunday for getting involved in the issue, calling it inappropriate.

CNN's Gabriella Schwarz, Tom Cohen, Casey Wian and Chris Welch contributed to this report.