MADISON, Wisconsin — Farmers on tractors joined a massive crowd surrounding Wisconsin's capitol Saturday to protest Republican moves to undermine unions and slash government services in a battle spreading across the United States.

Cheers and bells rang out as tractors bearing signs declaring "Walker's budget = war on workers, middle class" and "pull together -- support working families" slowly circled the towering statehouse which has been the scene of mass protests for weeks now.

The battle began when Wisconsin's newly-elected Republican governor Scott Walker proposed a controversial bill to strip public workers of bargaining rights.

Republicans in 36 other US states are also pushing for laws that would curtail unions, a major source of financial and mobilizing support for Democrats.

While protesters have taken to the streets across the country, the biggest fight has been in Wisconsin where Democrats fled the state on February 17 in an attempt to block the bill by denying Republicans a legislative quorum.

It intensified after Walker unveiled a budget with deep cuts to schools, state-subsidized health insurance and other critical services while cutting taxes for businesses.

"We've taken (pay and benefit) cuts and we'll take more," said Chris Carlsen, 55, who works for the state's department of transportation.

"When they turn around and give tax cuts to the corporations it's not okay."

Legislatures across the country are dealing with their most dramatic budget shortfalls in decades after the federal stimulus funds aimed at helping state and local governments through the worst of the economic downturn dried up.

With taxes increases off the table in most states, core services are taking a significant hit.

"If it was easy it's probably already been done," said Arturo Perez, a fiscal analyst with the National Conference on State Legislatures.

"What we hear from the states is that everything is on the table."

Most state and local governments are just beginning to tackle their budgets for the next fiscal year, which typically begins in July.

Wisconsin's governor said the bill stripping public workers of bargaining rights and increasing their pension and health care costs will save jobs and prevent tax increases for the middle class.

"While tough budget choices certainly still lie ahead, both state and local units of government will not have to do any mass layoffs or direct service reductions because of the reforms contained in the budget repair bill," he said in a statement after signing the bill into law Friday.

Democrats and demonstrators have vowed to keep up the fight, and have already begun efforts to challenge the bill in court and recall Walker and other Republican lawmakers.

"I'm afraid we're witnessing the death of the middle class," said Tom Bridge, 60, a retired unionized printer.

"We need unions because they set the gold standard of wages and benefits."

Dairy farmer Lou Miller, 63, said he's worried about growing income inequality in the United States and the erosion of middle and working class wages.

"If the working class disintegrates as it has been in the last 30 years farmers are going to have a hard time," he said.

"For me, it's a global issue of the concentration of wealth. Unions can be a buffer."