CHICAGO — They came to Soldier Field, not to cheer for the hometown Bears, but to challenge presidential candidates to represent the rainbow of working people on Main Street, not Wall Street.

At the unprecedented gathering of 17,000 union members and their families, seven Democratic presidential candidates stood on the 20-yard line and promised the cheering crowd on Aug. 7 that they would be labor’s voice in a new White House in 2008.

The AFL-CIO Working Families Forum was part of the biggest effort ever made by labor to influence and change the balance of power in the U.S. government. The debate was hosted by Keith Olberman and broadcast by MSNBC.

“Tonight is the beginning of the end for the most anti-worker administration in U.S. history,” John Sweeney, the federation’s president, told the World. “Any one of the candidates who participated tonight would represent a new day in America — they all have devoted many years to fighting for the needs of working Americans.”

The candidates who participated were Sens. Joseph Biden, Hillary Clinton, Christopher Dodd and Barack Obama, former Sen. John Edwards, Gov. Bill Richardson and Rep. Dennis Kucinich. Republican candidates and the only other Democrat, former Sen. Mike Gravel, did not participate.

Labor showed the candidates and everyone else, including hundreds of sometimes cynical media folks, that presidential debates are one thing but debates set up for ordinary working people are an entirely different thing. The unions turned this event into a job interview in which the candidates had to face workers with tough questions.

Steve Skvara, a retired steelworker from Union Township, Ind., approached the mike on crutches. Choking back tears, he asked, “How do I sit across the table from my wife who is sick and tell her that we can’t afford to pay for her health care? Please tell me what is wrong with this America and what are you going to do about it?” The crowd gave him a standing ovation.

Deborah Hamner came forward. She introduced herself as “the wife of George Junior Hamner. I loved him. He was killed in the Sago Mine disaster.” Hamner mentioned the six trapped miners in Utah. “What are you going to do about mine and workplace safety?”

Hospital worker Shirley Brown of Chicago stepped into the spotlight. She recounted four years of harassment, intimidation and illegal firings at Resurrection Health Care where she works. She told how she faced these attacks because she and her co-workers are trying to form a union at the hospital, “trying to exercise our basic human rights.”

“What will you do to change this?” she asked. “What will you do to see that we have the freedom to join a union?”

Jim McGovern, an Iraq veteran from Iowa, stepped up. When he got back home, he told the candidates, “I found that my job at Maytag had been outsourced. What can be done to help veterans return home to good jobs?”

Jorge Mulasano was another worker who stepped up to ask a question. He is a chef at the Sheraton Hotel and Towers. Born in Argentina, Mulasano became a U.S. citizen six months ago. Worried about immigrants, and especially the undocumented, he asked, “What are you going to do to provide a path to citizenship for so many other hard working people in this country?”

Candidates answered these and many other questions. Twenty thousand union members sent in the questions, from which Olberman selected some of the questions he asked. Other topics included the Iraq war, No Child Left Behind, the infrastructure and trade agreements.

Commentary afterward had Chris Matthews of “Hardball” warning that “if Republicans think they can ignore the concerns of that steelworker who spoke tonight, they are severely mistaken.”

The Democratic candidates seemed to have all heard labor’s message. Each of them came out for ending the war in Iraq. Edwards said 40,000 troops could come out now, Kucinich said all could come home now and the others favored concrete timetables for “safe and orderly” withdrawal. All said that ending the war would free up resources needed for building and for job creation at home.

Each of the candidates came out for creation of new jobs in the manufacturing sector, including through rebuilding the infrastructure. Clinton said jobs can be created by developing alternative, renewable, clean energy sources.

While all of the candidates deplored the consequences of “free trade,” only Kucinich called for outright repeal of NAFTA. The others said the agreements could be fixed to include workers’ rights and environmental protection.

Every one of the candidates strongly backed the Employee Free Choice Act, saying they would sign it into law.

They all backed universal health care coverage for all Americans. Kucinich said he backed HR 676, which sets up a single-payer national health insurance program and eliminates the role of private insurance companies.

The federation’s executive council decided July 8 not to endorse a particular candidate. Member unions are free to endorse in the primaries. But it’s expected the entire labor movement will back the Democratic nominee in the general election.