Earlier this month, AFL-CIO President Richard Trumka confirmed rumors that the Big Labor coalition would move to amend its bylaws to allow non-union members — in particular, liberal activists from the Sierra Club and the National Council of La Raza — to join up. Some of the AFL-CIO’s member unions balked at the idea though and the labor federation is now reportedly scaling back those plans.

The Wall Street Journal reports:

Building-trades unions in particular bristled at granting an enhanced role to environmental groups such as the Sierra Club, which opposes some projects the union supports, such as the Keystone XL Pipeline.

“Giving people a seat where they have governance, and they don’t represent workers, that was a bridge too far for lots of folks,” said Sean McGarvey, president of the federation’s Building and Construction Trades Department. The department coordinates lobbying and other programs for unions that collectively represent 2 million laborers, ironworkers, painters and others.

Following sometimes contentious talks, the federation now plans to expand membership of groups that focus on core issues, such as centers that typically advocate for low-wage and immigrant employees. Several such groups are already affiliated with the federation and pay some dues.

A spokesman for the AFL-CIO told the Journal “its leaders never intended to give advocacy groups a governance role” in setting the AFL-CIO’s agenda, but the member unions were evidently not convinced. For one thing, those non-union groups have already gained considerable clout in setting the AFL-CIO’s agenda.

Environmental groups successfully pushed the AFL-CIO leadership in February to not endorse the Keystone pipeline project, angering many in the building trades unions who have endorsed it. Making that relationship even tighter is apparently too much for many and file union members.

The apparent solution is to allow nonunion people to join AFL-CIO-affiliated nonprofit groups, but to not give them full membership in the AFL-CIO itself. The measure will be put to a vote during the AFL-CIO’s quadrennial convention in Los Angeles next month.

Even Trumka himself has voiced concerns over whether the AFL-CIO will be “diluted” and turn away from its traditional role as a worker advocate by the proposed changed.

At a breakfast hosted by the Christian Science Monitor Thursday, he briefly alluded to the dissension within the ranks but indicated he still intended to pursue closer ties with liberal groups, rather than rely on the ad-hoc coalitions the liberal movement has used in the past.

“What we have to do is to get the progressive groups together and form strategic partnerships … and get past the your issue/my issue situation,” Trumka said. He added that relations with those groups must be “not transactional, but transformational.”