Millions of unionized workers in the U.S. will see their contracts expire over the next year, and labor leaders say that even nonunion workers should hope those contract negotiations go well for the labor movement.

The heads of the unions affiliated with the labor federation AFL-CIO said in a Tuesday conference call with reporters that they expect new contract negotiations to have a noticeable effect on the broader economy because of the issues up for negotiation and the number of people covered by those contracts.

The AFL-CIO, which includes unions representing more than 12 million workers, said it estimates that roughly 5 million union members work under labor contracts that are set to expire in 2015.

“We’re all in this together,” said Lee Sanders, president of the public sector union AFSCME.

He was not just referring to union members. As union membership has declined over recent years, organizations such as the AFL-CIO have sought ways to build support and power outside their formal membership. That means moving beyond their bread-and-butter work of collective bargaining and traditional organizing to include more support for other progressive causes. Collective bargaining, formalized through the 1935 National Labor Relations Act, is the process by which unions negotiate the pay, benefits and workplace conditions of their members.

The unions hope that their work in negotiating for their members’ wages and benefits will gain support from the broader progressive movement. If unions are able to bargain effectively for their members, they said, it benefits everyone. American Federation of Teachers President Randi Weingarten argued that higher union wages have a ripple effect throughout the wage-earning economy.

“What bargaining is to us is, how do we lift all boats?” she said. “How do we create a virtuous cycle and ensure that families and communities have more money in their pockets?”

Some public sector union leaders went a step further, saying that they were using contract negotiations to advocate for good public policy. American Postal Workers Union President Mark Dimondstein noted his union’s advocacy for a plan that would allow the post office to provide financial services in low-income communities. “We’re approaching our negotiations as bargaining for the public good,” he said.

The labor leaders spoke from Atlanta, where they assembled for a meeting of the AFL-CIO’s executive council. Hundreds of miles away, in Wisconsin, local unions are battling what they see as a major threat to collective bargaining: the state’s impending passage of right-to-work legislation, would forbid unions there to collect automatic representation fees from nonunion workers covered by union contracts.

The Wisconsin legislation, a blow to organized labor in what was once a union stronghold, adds urgency to the leaders’ insistence on organized labor’s continued relevance to nonunion workers. “History shows and the current situation also demonstrates that if we are serious as a nation about addressing the issue of inequality, then we should be supporting workers forming unions,” said AFL-CIO organizing director Elizabeth Bunn.