Unions and activists are rushing to the Wall Street occupation to return the nation’s focus to the executives, bankers, and politicians who got us into this mess.

Union members and other New Yorkers poured into Foley Square in downtown Manhattan yesterday, the staging area for a march to the financial district where Occupy Wall Street has set up shop since September 17.

The crowd quickly filled the square and jammed surrounding sidewalks. A maze of metal police barricades tried to keep vehicle traffic moving by hemming in the protesters. That effort failed in the face of the overwhelming crowd, which spilled onto adjoining streets. Press reports put the crowd between 10,000 and 20,000.

Occupy Wall Street first gained mainstream press attention when members were pepper-sprayed by the New York police, and again when 700 were arrested Saturday trying to cross the Brooklyn Bridge. They’ve been gaining traction as their message, “We are the 99%,” reaches a public facing unrelenting wage cuts, layoffs, and foreclosures.

New York’s Transport Workers Local 100 was among the first unions to endorse the occupation.

“We endorsed Occupy Wall Street because we agreed with 99 percent of what the protesters were saying,” said Marvin Holland, director of community action for the union, which represents 38,000 bus and train system workers.

“They’re 100 percent right that banks caused this problem. We’ve had rank-and-file members of TWU Local 100 there since day one.”

Arthur Cheliotes, president of a local that represents 8,000 city workers, said members came out in support because “they know Wall Street is the root of the problem.”

By October 5, a substantial portion of the labor movement in New York City had endorsed the occupation. The AFL-CIO executive committee gave its blessing on Wednesday, as 13 national unions issued statements of support.

Some went further: the executive council of the giant SEIU 1199 health care local voted to feed the occupiers for a week and dispatched a task force to train protesters in first aid.

Regina Grissom, an 1199 executive council member, said the union doesn’t buy into attempts to divide the occupiers—stereotyped as young, white, out-of-work folks—from labor support. She said 1199, whose members are majority people of color, is building support for the occupation in communities and churches.

“It’s not what we look like, but what we do together,” said Grissom, a clerk in a maternity clinic. “This is a labor issue, because whether you’re in a union or not, you’re under attack. We have to band together so that we can strike a mighty blow.”

Occupy Together

Marches and occupations under the “Occupy” heading are planned in dozens of U.S. cities. Twenty-four were arrested protesting foreclosures at Bank of America in Boston on Friday, and an occupation is planned to start today in Washington, D.C.

In New York, banners, signs, hats and T-shirts announced the presence of union transit workers, university staff, communications workers, musicians, store clerks, teachers, and health care workers. But the majority of the crowd seemed to be unaffiliated with any union group. “Lost my job, found an occupation,” said one man’s sign.

“Banks got bailed out, we got sold out,” marchers chanted, echoing the 2008 factory occupation in Chicago by workers at Republic Windows and Doors. “How do we fix the deficit? End the wars, tax the rich!”

Middle school students marched with their parents behind colorful banners, and carried signs demanding the city bring back art teachers. City University of New York staff formed a large contingent with bold red signs saying “PSC Supports You.”

Members of the Communication Workers handed out flyers urging passersby not to upgrade to the newest iPhone until Verizon settles a fair contract. They said they came because Wall Street occupiers joined a picket line at Verizon headquarters last week.

How Do Unions Fit In?

Disgusted and dismayed after governors from Democrat Andrew Cuomo to Republican Scott Walker blamed teachers and firefighters for the nation’s economic problems, unions are thrilled to see public attention focused on bulging corporate profits, scofflaw bankers, and the politicians who love them.

Unions are embracing the occupation as a platform for raising demands they’ve spoken about for months without similar traction.

The Strong Economy for All Coalition, which mounted the May 12 march that brought at least 10,000 to Wall Street, is refreshing its demands that government stop the $5 billion tax cut for New York’s richest, restore the billions cut from state schools and other services, and create good jobs now.

“The straw that broke the camel’s back for us was when the millionaires’ tax wasn't continued,” Holland said. “That showed that all this talk of shared sacrifice in Albany really just meant working people sacrificing.”

The tax cut for New York state’s millionaires won’t take effect until December 31, giving the unions and occupiers time to reverse the governor’s gift to the state’s richest residents.

The coalition is also calling for Congress to pass the American Jobs Act and fair-share tax laws, including the Buffett Rule, which would lift tax rates on top earners to 1990s levels.

The marriage of the occupiers’ inspiration, creativity, and humor with the strategic heft of the unions could be a potent force.

While mainstream media outlets attempt to pigeonhole the Occupy Wall Street phenomenon as a freakish carnival, the occupiers say their message should have almost universal appeal. “We come to you at a time when corporations, which place profit over people, self-interest over justice, and oppression over equality, run our government,” the group said in a statement voted on September 29. “We write so that all people who feel wronged by the corporate forces of the world can know that we are your allies.”

In response to media scolding that the protest has unclear demands, one woman carried a sign, reading “You want a demand? We want a future!”

Union support blossomed, Cheliotes said, once labor decided the occupation would stick.

Still, labor is recognizing it can’t control what’s happening—a refreshing change from scripted gatherings featuring messages tested by focus groups.

Most unions seem savvy enough to know they can’t drive the occupation but they can provide the resources that will give it staying power and let it grow.

While carefully noting they can’t—and don’t want to—dominate the occupation, they’re also hoping to piggyback on some of its energy. The union-community Strong Economy for All coalition will tap into the enthusiasm to hold actions against banks and billionaires in coming days, as will a similar coalition in Chicago.

The unions are also registering practical solidarity. TWU Local 100 has sued the city to prevent it from forcing union bus drivers to haul protesters to jail.

“Right after we endorsed Occupy Wall Street, the city used our buses to hold people the cops were arresting and made our folks drive them to jail,” Holland said. “It was totally wrong and we're going to fight it.” The union goes to court on Monday.