(CNN) -- Wisconsin's battle over labor rights shifted toward a series of recall elections Wednesday after the state's highest court reinstated a bitterly contested law that restricts collective bargaining for state workers.
Unions filed a separate federal lawsuit challenging the law Wednesday, but Wisconsin Gov. Scott Walker, who pushed the measure through the state Legislature, said it was time to "move forward."
Six of the 19 Republicans in the state Senate will face recall votes July 12 after they voted for legislation that curbs bargaining rights for Wisconsin public employees, while three of the 14 Democratic senators who fled the state in a last-ditch effort to block the bill are being targeted by Republicans in separate votes the following week.
Each side accuses the other of being the puppet of out-of-state special interests that have joined the battle since February. State Republicans are trying to force runoffs in their races by recruiting "protest candidates" to split anti-incumbent sentiment, Wisconsin GOP chief Stephan Thompson acknowledged Tuesday.
"The protest candidacies will give the Republican senators time to communicate with their constituents and ensure that voters have a chance to learn about the differences between the Republican plan to grow jobs and reduce spending, and the Democrats' record of job-killing taxes and budget deficits," Thompson, the party's executive director, said in a written statement.
Democrats have blasted the moves as an attempt at "gaming the system," and party Chairman Mike Tate has rejected calls to respond in kind.
"We cannot and will not stoop to the Republicans' level by encouraging candidates to lie about their party affiliation or recommending that people try to deceive voters," Tate said in a weekend statement.
Tuesday's 4-3 ruling by the state Supreme Court was a major victory for Walker, who argued that the anti-union legislation was needed to close a $137 million budget gap and to control skyrocketing benefit costs for public employees. It passed despite a storm of protests by public employees, including teachers, police and firefighters, who besieged the state Capitol for three weeks in February and March.
Protesters returned in early June as state lawmakers worked to finish a budget, setting up a tent city dubbed "Walkerville" outside the Capitol.
Under the law, all public workers except police and firefighters -- some of whose unions backed Walker's 2010 campaign -- will be required to pay a larger portion of their retirement plan contributions and health care premiums. Raises will be tied to the rate of inflation, unless state voters approve an exception. Unions will be required to hold a new certification vote every year and will no longer be allowed to collect dues from workers' paychecks.
Democrats called the bill an attempt to gut public-sector labor unions, one of their core constituencies. They had argued that the GOP-led Assembly and Senate failed to provide sufficient public notice before passing the legislation in March, and a judge in Madison had blocked the law from taking effect until Tuesday's decision, which rejected that argument.
The AFL-CIO, which condemned Tuesday's ruling, went to federal court with its allies Wednesday to challenge the law. The unions argue that the law violates workers' rights under the U.S. Constitution to organize and bargain collectively.
"When a legislature discriminates among classes of workers, especially when doing so has more to do with political payback than with any legitimate reasoning, the law has been violated," AFL-CIO state President Phil Neuenfeldt said in a statement announcing the case. The unions are not challenging the portion of the law that raises workers' benefit payments, he said.
At a bill-signing event Wednesday afternoon, Walker declined comment on the new challenge. But he said the Tuesday ruling allows his "Budget Repair Bill" to take effect by the start of the state's fiscal year July 1.
"The Supreme Court of the state of Wisconsin has been heard. I think overwhelmingly, people around the state believe legal action is done," Walker said. "It's time for us to move forward, and ultimately I think that's going to to prevail."
Opponents are also mobilizing to recall Walker, whose poll ratings have dipped sharply since he took office in January. But Wisconsin law protects elected officials from recalls until they have held office for a year.