Wisconsin Gov. Scott Walker signs a right-to-work bill into law Monday in Brown Deer, Wis. (AP Photo/Milwaukee Journal-Sentinel, Mike De Sisti)

President Obama, in a rare move that inserted himself directly into Republican presidential politics, issued a statement Monday night sharply criticizing Wisconsin Gov. Scott Walker for signing a right-to-work bill into law that marks a major blow to organized labor.

The Wisconsin law, which prohibits unions from collecting mandatory fees from workers who are not union members, was signed into law on Monday by Walker, who is preparing to run for president in 2016 and has recently surged to the top tier of Republican contenders. Walker's crusade against public-sector unions four years ago made him a national GOP star.

Obama rarely comments on state laws, but by wading into the Wisconsin debate he may help Walker in the crowded Republican primary campaign by elevating the Wisconsin governor above the other likely GOP candidates.

In his statement, Obama said the "anti-worker law in Wisconsin will weaken, rather than strengthen workers in the new economy."

"Wisconsin is a state built by labor, with a proud pro-worker past," Obama said. "So even as its governor claims victory over working Americans, I’d encourage him to try and score a victory for working Americans -- by taking meaningful action to raise their wages and offer them the security of paid leave. That’s how you give hardworking middle-class families a fair shot in the new economy -- not by stripping their rights in the workplace, but by offering them all the tools they need to get ahead."

Obama is not the only prominent Democrat to weigh in recently on the debate over organized labor. Hillary Rodham Clinton, the former secretary of state and likely 2016 Democratic presidential candidate, spoke about the issue last week in her address at an EMILY's List gala. Although her remarks were interpreted by some as a reference to Walker, she did not mention the governor by name or the Wisconsin law specifically.

“We know that the American middle class was built in part by the right for people to organize and bargain on behalf of themselves and their colleagues," Clinton said. "This is one of those important issues that is not just for labor union members. This is an important issue for everybody who works because if there is not a balance of power in the workplace, everybody will suffer.”