Facing what AFL-CIO chief Richard Trumka called a “crisis” of membership, officials took the dramatic step at their annual convention of adopting a resolution that invites anyone in the country to join, regardless of union affiliation. The move faced stiff resistance from union officials who fear the AFL-CIO’s primary mission of representing workers will be left behind if the federation becomes a mouthpiece for liberal and progressive groups.

Despite the resistance, the resolution was adopted without a single “nay” vote being heard in the convention hall.

Supporters of the move to a broader membership standard said the AFL-CIO can no longer define itself by the narrow collective bargaining laws that are being challenged across the country.

“This resolution issues an invitation to every worker in the United States to join the movement for social justice,” said Lee Saunders, president of the American Federation of State, County and Municipal Employees (AFSCME). “The freedom to choose to be part of this movement must be a freedom available to every worker.”

The decline of labor membership has been a dominant topic at the labor federation’s event, where officials have been fervently debating how to reverse the trend.

In his keynote address on Monday, Trumka came down decidedly on the side of a “big tent” labor movement, noting that the percentage of workers who were unionized dropped to 11.3 percent last year.

“We must begin, here and now, today, the great work of reawakening a movement of working people,” Trumka said.

The AFL-CIO intended for the convention to be a gut-check for labor, and spent months organizing committees of student representatives, academics, civil rights advocates and union officials to discuss how to keep unions alive in the years to come.

Trumka said labor must include new workers — not to increase union dues, but to create change for everyone.

“Not so we can have bigger unions, but so we can together make all working peoples’ lives better,” he said. “Because the success of our movement is not measured in the members we organize, or the politicians we elect. It is measured by the progress of working people — all working people — by the lives we lead, by the hopes and dreams we make real together.”

But many fear the resolution will lead to liberal groups like Sierra Club or MoveOn seeking membership in the AFL-CIO, drawing the federation deeper into political causes that are separate from members’ bread-and-butter concerns.

Harold Schaitberger, president of the International Association of Fire Fighters, told The Hill on Sunday that, “this is the American Federation of Labor. We are supposed to be representing workers and workers’ interests. ... We are not going to be the American Federation of Progressive and Liberal Organizations.”

Larry Cohen, president of the Communication Workers of America, denied that the resolution was intended to allow direct affiliation with groups like Sierra Club.

“First of all, they aren’t going to raise the funds to join. Nobody ever talked about people joining fully and not having at least that obligation. I think what we intended all along, speaking for me and [AFSCME President] Lee Saunders, was to figure out ways how to increase work with greens and so on,” Cohen said.

Approval of the resolution was helped by the fact that unions will be allowed to decide for themselves whether to invite non-members into the fold, Cohen said.

“When you read [the resolution], it’s about unions that support this will do it. Those who don’t won’t have do it. You can’t force people to do this,” Cohen said.

The adoption of the resolution was a victory for Working America, the AFL-CIO’s community affiliate that represents 3 million people who work outside of collective bargaining agreements.

Working America is now authorized to consult with the AFL-CIO president, subject to approval by the federation’s executive council, to adopt a members’ dues structure and develop advocacy in the workplace.

Karen Nussbaum, Working America’s executive director, told reporters on Monday that non-union workers — especially people who have been laid off or who voted to unionize in losing union elections at their work sites — can come to her group.

“Those folks are now going to find a way to have a home through Working America and with affiliates, and we have got several examples that we are going to build on from there,” Nussbaum said.

The resolution also says the AFL-CIO should “deepen” its relationship with worker centers, the nonprofit groups that have been organizing low-wage workers, including those behind the recent fast-food restaurant strikes.

With union members only making up 11.3 percent of the workforce last year, worker centers are key to the AFL-CIO’s aspirations of becoming a broader social movement, observers say.

“They are a vital part of what labor is doing going forward, with unions trying unconventional ways in reaching non-union workers,” said Harley Shaiken, a University of California, Berkeley professor who specializes in labor issues.

But many in labor said they have deep reservations about the move.

Some worry that expanding union membership beyond dues-paying members could undermine collective bargaining agreements that are already in place.

“We are concerned as we move forward so we don’t undermine the work we have already done,” said Lou Paulson, president of the California Professional Firefighters. “We don’t want the walls knocked down as we try to fix the foundation.”

That sentiment was overwhelmed, however, on the floor by other convention attendees, many of them AFSCME members, who resoundingly backed the resolution. Many of them praised Working America as a boon to unions that is helping labor organize and become more politically effective.

North Shore Labor Council President Jeff Crosby from Massachusetts offered what he called a “pragmatic, practical argument” for the resolution.

“You can’t raise the roof of the House of Labor if the floor is caving in,” Crosby said.

“We have tried exclusion in the past. It has failed.”