For union folks like Sean McGarvey, the issue comes down to this: Change may necessary, but not at the cost of one’s own identity. And that is the danger of what AFL-CIO President Richard Trumka plans for the labor movement.

McGarvey is president of the AFL-CIO’s Building and Construction Trades, a two-million-member coalition group within the larger labor federation.

So it was a sign of major discontent with the ranks when he publicly slammed Trumka’s plans to strengthen ties with non-union activist groups like the Sierra Club.

“Giving people a seat where they have governance, and don’t represent workers, that was a bridge too far for lots of folks,” he told the Wall Street Journal recently.

Trumka’s people disputed that that was ever the plan, saying they “never intended to give advocacy groups a governance role” in setting the AFL-CIO’s agenda. Rather, the new plan is the groups would join an existing labor-backed nonunion activist group called Working America.

But the rank-and-file are skeptical – with good reason. The nonunion groups have already shown they have considerable clout over labor’s agenda. And now they may get more.

Trumka himself conceded to USA Today in an Aug. 7 interview that it could “dilute” the AFL-CIO but indicated he didn’t think Big Labor could survive otherwise.

The debate will become clearer in the second week of September at the AFL-CIO’s quadrennial convention in Los Angeles. There, Trumka will push for a vote to amend the federation’s by-laws.

The AFL-CIO has been moving in this direction for years under Trumka and his predecessor, John Sweeney. Both have struggled to revive the AFL-CIO, which has seen its membership decline by half since 1983. The union movement needs more people, period.

Trumka seems taken in particular with the grassroots groups like Occupy Wall Street. He wants to harness that energy for Big Labor.

“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,” he said at an Aug. 29 breakfast hosted by the Christian Science Monitor. The relationships must be “not transactional, but transformational.”

That kind of talk is all throughout the AFL-CIO’s convention literature. An “outreach and engagement” report includes a proposal to “enable more people to be part of the labor movement and create new models of representation.”

The section explains that “many feel that labor should pilot structural changes that would enable some type of formal affiliation for worker’s organizations that do not engage in collective bargaining.”

But what does “worker’s organization” mean in this context? Two of the names that come up the most often in Trumka’s plans are the Sierra Club and the National Council of La Raza, groups whose primary issues are, respectively, the environment and immigration. Those are issues that sometime put them in direct conflict with labor groups.

That has many worried that Trumka’s alliances will effectively give those groups veto power over the federation’s agenda. The Building and Construction Trades, for example, has endorsed the Keystone XL pipeline project but the AFL-CIO itself hasn’t, a result of intense lobbying by the environmental movement.

Instead, the AFL-CIO put out a bland statement in February saying that it endorsed pipeline projects in general without ever mentioning Keystone. That was almost a year after Laborers International Union of North America President Terry O’Sullivan berated the AFL-CIO leadership in a statement over the pipeline:

“We’re repulsed by some of our supposed brothers and sisters lining up with job killers like the Sierra Club and the Natural Resources Defense Council to destroy the lives of working men and women.”

That was back when the labor/green alliance was just “transactional,” to use Trumka’s phrase. How many of the existing rank and file are onboard now that Trumka wants to make it “transformational”? We’ll find out when he pushes to change the rules this month.