Dressed in orange in support of unionized public workers, state Rep. Elizabeth Coggs (D-Milwaukee) listens to Assembly debate at the state Capitol in Madison, Wisconsin. (AP Photo/Wisconsin State Journal, Michael P. King)

WASHINGTON (AP) — Labor unions at the heart of a burning national disagreement over the cost of public employees want to frame the debate as a civil rights issue, an effort that may draw more sympathy to public workers being blamed for busting state budgets with generous pensions.

As part of that strategy, unions are planning rallies across the country on April 4 — the anniversary of Martin Luther King Jr.'s assassination. Union officials want the observances in dozens of cities to remind Americans that King was supporting striking sanitation workers in Memphis, Tenn., the night he was shot.

By portraying collective bargaining as a human rights issue, union officials hope the rallies can help fuel a backlash against Republicans in Wisconsin and other states trying to curb collective bargaining rights for public employees.

"This is a fight for workers, this is a fight for the middle class, this is a fight to try to stave off the shift in power and wealth that is starting to become gross," said Harold Schaitberger, president of the International Association of Fire Fighters.

The planned rallies on the 43rd anniversary of King's death are part of a coordinated strategy by labor leaders to ride the momentum of pro-union demonstrations and national polls showing most Americans support collective bargaining rights as Wisconsin Gov. Scott Walker and other GOP leaders in states fight to reduce or strip those benefits.

Walker has argued that collective bargaining is a budget issue. On Friday, he signed into law a bill the strips nearly all collective bargaining benefits from most public workers, arguing the move will give local governments flexibility in making budget cuts needed to close the state's $3.6 billion deficit.

"That's something people forget about Dr. King," said Liz Shuler, secretary-treasurer of the AFL-CIO, the nation's largest labor federation. "We all know about his work in the civil rights movement, but he was also a workers' rights advocate."

It's also another signal that labor leaders are trying to broaden the coalition of groups speaking out against efforts to limit collective bargaining rights for public employee unions. Unions are coordinating the rallies with the NAACP, the Leadership Conference on Civil and Human Rights and other civil rights, religious and progressive groups.

"Dr. King lost his life struggling to help sanitation workers — public sector employees — achieve their goals for a dignified existence as workers," said Wade Henderson, president of the Leadership Conference. "We think that's an extraordinary backdrop in which to frame the debate over what's taking place in the country today."

When King traveled to Memphis in 1968, he was lending support to more than 1,100 black sanitation workers who were on strike seeking better working conditions, higher wages and benefits, and union recognition.

Daniel Walkowitz, a labor historian at New York University, said the gesture was typical of King's later years, in which the targets of his activism were less often the legal barriers to civil rights for blacks. More often, King was focused on lack of employment and educational opportunities for African-Americans.

"Tying the rallies to King is an interesting strategy because it does draw upon King's understanding that the problems of labor were problems of civil rights," Walkowitz said.

Walker argues that the sweeping step against collective bargaining is necessary to balance the budget not only over the next two years but into the future. He said he wouldn't compromise on the issue or on anything that saves the state money.

But union leaders see it as a fight for middle class rights. Wisconsin unions had agreed to cuts in pension and health benefits as long as they could keep collective bargaining rights. Labor leaders say Walker's refusal to compromise shows he wants to leave unions toothless and cripple their political clout.

While unions are on the verge of losing power in Wisconsin, Ohio and other states, union leaders believe they are winning the war of public opinion and pulling in broader support.

"The movement is bigger than just the labor movement," United Steelworkers President Leo Gerard said. "What we're seeing is an awakening about the importance of collective bargaining."

Labor leaders already have pledged to pour more than $30 million into a push to stop legislation in dozens of states that seeks to limit bargaining rights of public worker unions or otherwise curb union power. Union officials are also helping mobilize demonstrations in state capitols and spending money on recall campaigns against GOP officials who support efforts to curb union rights.