WASHINGTON, July 9 (Reuters) - U.S. Democratic presidential candidate Hillary Clinton will meet privately this month with leaders of the nation's largest labor federation as she seeks to prevent a revolt by union members infuriated by her cautious stance on a looming trade deal, labor sources told Reuters.
Leaders with the AFL-CIO, an umbrella group for 56 member unions representing more than 12.5 million workers, will press her on issues such as trade, infrastructure and the types of officials she would name to the Federal Reserve's Board of Governors.
During its gathering in Silver Spring, Maryland, on July 29-30, the AFL-CIO's executive council will also have separate meetings with Clinton rivals former Maryland Governor Martin O'Malley and U.S. Senator Bernie Sanders, whose presidential candidacy has been gaining steam among labor union activists.
Aides to O'Malley and Sanders confirmed they would attend the meeting. Clinton's campaign declined to comment on her attendance but other sources said she is expected.
Trade will likely be the No. 1 issue at the two-day gathering of the federation, which represents workers in a wide range of professions, from brick layers to machinists to nurses.
Labor sources said the council will press Clinton to oppose the Pacific Rim trade deal the Obama administration is finalizing. The issue is a difficult one for Clinton, who was secretary of state in President Barack Obama's first term and an influential player in the administration's effort to build stronger ties with Asia. Obama administration officials view the Trans-Pacific Partnership as a crucial part of its "pivot" to Asia.
While Sanders strongly opposes the TPP, Clinton has stopped short of repudiating it. She has called for strong worker protections in any deal but said she would not take a position until she sees the final details.
"I was incredibly disappointed that we couldn't get leadership from that campaign against fast track," outgoing Communications Workers of America President Larry Cohen said of a preliminary step in completing the trade deal.
Cohen now volunteers for the Sanders campaign, acting as an unofficial labor surrogate.
Clinton plans to deliver a speech on the economy on Monday in New York. Sanders, a democratic socialist, has attracted growing support from progressives with his criticism of large corporations and calls to break up Wall Street banks.
While Clinton remains the Democratic front-runner, Sanders has narrowed his gap with her in polls and is drawing big crowds in the early voting states of Iowa and New Hampshire, as well as in others such as Maine and Wisconsin. Labor leaders say they will watch Clinton's speech closely.
The AFL-CIO has not said whether or when it will endorse a Democratic primary candidate in the 2016 race. The executive council meeting will be a key step in its deliberations.
Organized labor is a crucial base of support for the Democratic Party. The AFL-CIO's endorsement would provide a huge advantage to a presidential candidate, given the large role that labor plays raising money and mobilizing voters for candidates.
The federation could choose to hold off on endorsing any candidate until the primary contests are over. In 2008, the federation's unions were split between Clinton and Obama. It ultimately endorsed Obama in June of that year when it was clear he was going to be the Democratic nominee.
The AFL-CIO meeting adds to pressure on Clinton to provide specifics in Monday's speech. She has so far spoken mostly in broad brush strokes addressing economic inequality and ensuring that workers have access to paid family leave.
Michael Podhorzer, AFL-CIO political director, said it will be "absolutely essential" for candidates to provide specifics on their policies ahead of the meeting.
"The council members will expect that," Podhorzer said.
Highlighting efforts by the Clinton campaign to court organized labor, John Podesta, her campaign chairman, will host leaders of various unions for an informal gathering at his home in Washington on Tuesday.
Hillary for America spokesman Jesse Ferguson said Clinton has a "life-long record" defending labor priorities such as organizing and collective bargaining.
"This campaign is working hard to earn the support of everyone involved in the labor movement," Ferguson said.
While the AFL-CIO executive council has not endorsed a candidate yet, some local unions have made public gestures supporting Sanders, prompting the federation's president, Richard Trumka, to urge them to stay neutral for now.
The AFL-CIO's endorsement process is an unwieldy one. The unions under its umbrella all have their own priorities. Machinists and communications workers are particularly concerned about trade issues but other unions, such as those representing teachers, are focused on issues such as public-employee collective bargaining.
Steve Abbott, a leader for a local union in Iowa that represents communications workers, is one of some 3,500 individuals from within the labor movement who have joined the all-volunteer grassroots group Labor for Bernie. He emphasized that he was supporting Sanders as an individual, not as a leader of the local union, and said the trade deal prompted him to back Sanders.
"He absolutely came out against it. She waffled," Abbott said. (Reporting by Amanda Becker and Luciana Lopez in Washington; Editing by Caren Bohan and Lisa Shumaker)