AFL-CIO President Richard Trumka is expected to get another 4-year term as head of the nation's largest labor federation Alex Wong/Getty Images

The AFL-CIO, the country’s largest labor federation, kicked off its quadrennial convention in Los Angeles Sunday on the heels of the announcement by its president Richard Trumka that it was considering opening its ranks to millions of non-union members in a bid to inject political power into the nation’s sagging labor movement.

"The labor movement really is at a crossroads, and we have some decisions to make," Trumka said in an interview with Reuters several days before the gathering.

At center stage in Trumka’s calculus is the decades-long political clash between big labor and corporate America, a battle that he said has overwhelmingly favored the latter.

"During the last 20 years, corporate America went for the final victory and used every front they could to take away workers' rights," Trumka said. "So it's important for us to come together to...function like the majority we are, rather than little silos that can be marginalized."

To that end, this year’s convention is seeking a wider coalition of politically progressive entities in a bid to transform the federation’s effectiveness as part of a broader permanent political coalition.

Community organizations, non-union labor groups, religious leaders and other potential allies will try to help the AFL-CIO figure out its four-year blueprint for bolstering the status of workers.

"Our opposition is well-financed and determined...We're too small to do it alone," he told the Los Angeles Times Thursday.

Echoing Trumka’s call on the opening night was an upbeat address by Sen. Elizabeth Warren, D-Mass., who proclaimed that the cause of the labor movement was inseparable from a wider agenda to protect the average American from special corporate interests.

“On almost every issue of economic concern, our values are America’s values, and our agenda is America’s agenda,” she said.

She said that over the course of the last century, it has been labor organizations which have stood up against “powerful interests.”

“At every turn, in every time of challenge, organized labor has been there, fighting on behalf of the American people,” she said.

Warren, who is her state’s freshmen senator and serves on the Senate Banking Committee, has been lauded by labor groups for her resolute stance on issues from Wall Street regulation to consumer protection.

While the AFL-CIO is easily the nation’s largest labor bloc, representing more than 12 million workers and 57 member unions, its political power has declined alongside the broader shrinking in the labor movement as a whole. The proportion of the U.S. workforce with union representation was 11.3 percent in 2012, down from 20.1 percent in 1983, when Bureau of Labor Statistics data began.

Tom Kutsch contributed to this report, with wire services