The Occupy Wall Street movement’s political breakthrough came Wednesday, as leaders of the Congressional Progressive Caucus and the Congressional Black Caucus joined Senator Bernie Sanders, I-Vermont, in endorsing the burgeoning national challenge to corporate greed and corrupt politics.

On a day that saw thousands of union members, community activists and supporters of New York’s Working Families Party rallied in solidarity with the New York protests, Congressman John Larson, the Connecticut Democrat who is the fourth-ranking member of the party’s House Caucus announced that, “The silent masses aren’t so silent anymore.”

Nor were progressive groups. While some unions, especially the United Steelworkers nationally and the Tranport Workers Local 100 in New York, provided early backing, they were ouliers—until Wednesay. Liberal groups such as MoveOn and Democracy for America gave their blessings and started raising money to support the initiative. The 1.4 million member Teamsters union signed on, with President James Hoffa saying: “No one should be surprised that Occupy Wall Street is gaining support and spreading quickly around the country. The American Dream has disappeared for students, whose reality is debt and unemployment. The dream disappeared for workers forced to take wage cuts by employers sitting on billions of dollars in profits. The dream disappeared for working families who paid too steep a price for Wall Street’s greed, stupidity and fraud.”

“It’s clear what this movement is all about. It’s about taking America back from the CEOs and billionaires on Wall Street who have destroyed our nation’s economy. It’s about creating good jobs. It’s about corporate America treating its workers and customers with honesty and fairness and paying its fair share to stimulate the economy,” argued Hoffa. “Teamsters all over the country are participating in Occupy Wall Street events, and I support and encourage them. We stand in solidarity with Americans who want better lives for themselves and for future generations.”

Similar signals came from key members of Congress.

Not surprisingly, it was Sanders who offered the most full-throated support of the movement. At the Campaign for America’s Future “Take Back America” conference, he declared: “We have the crooks on Wall Street, and I use that word advisedly—don’t misquote me, the word is ‘crooks’—whose greed, whose recklessness, whose illegal behavior caused this terrible recession with so much suffering. We believe in this country; we love this country; and we will be damned if we’re going to see a handful of robber barons control the future of this country.”

Remarkably, considering the caution of so many elected officials with regard to the protests, Sanders actually called for a toughening of the movement’s anti–Wall Street message. “I applaud those protesters who are out there, who are focusing attention on Wall Street, but what we’ve got to do is put meat on that bone,” he said. “We’ve got to make demands on Wall Street [and] break those institutions up.”

Echoing Sanders, with who she appeard on Tuesday, was Congresswoman Barbara Lee, the California Democrat who has long been a key player in the Congressional Black Caucus and the Congressional Progressive Caucus. “All of us should join that movement,” said Lee.

On Wednesday, the current co-chairs of the Congressional Progressive Caucus issued a joint statement celebrating the Occupy Wall Street movement.

“We have been inspired by the growing grassroots movements on Wall Street and across the country. We share the anger and frustration of so many Americans who have seen the enormous toll that an unchecked Wall Street has taken on the overwhelming majority of Americans while benefitting the super wealthy. We join the calls for corporate accountability and expanded middle-class opportunity,” said Congressmen Keith Ellison, D-Minnesota, and Raul Grijalva, D-Arizona. “Throughout the summer, CPC Members listened to Americans nationwide describe how it feels to be on the wrong side of the wall between the rich and the rest of us. During the Speakout for Good Jobs Now! tour in New York City, Detroit, Milwaukee, Oakland, Minneapolis, Miami and Seattle, we heard compelling stories of Americans struggling to live the American dream while CEO’s and the super rich were given more taxpayer handouts. We stand with the American people as they demand corporate accountability and we support their use of peaceful means to improve America.”

“I’m so proud to see the Occupy Wall Street movement standing up to this rampant corporate greed and peacefully participating in our democracy,” said Congresswoman Louise Slaughter, D-New York, who added: “It’s time for all Americans to pay their fair share.”

Congressman Dennis Kucinich, an Ohio Democrat who sought the Democratic nomination for president in 2004 and 2008, was equally enthusiastic:

To the young men and women who are braving the overreaction of local authorities to raise their voices against the corruption and manipulation of our nation that emanates from Wall Street: I say to you that your presence is making a difference. You are exercising the right every American holds most dear, the right of freedom of expression, and with that expression you are finally getting the attention of the nation.

Wall Street banks got billion dollar bailouts but the American people get austerity. Fourteen million Americans are out of work. 50 million people don’t have health insurance and a million homes a year are lost to foreclosure. Our policies take the wealth of the nation and accelerate it into the hands of the few.

We need a government of the people and for the people. We need a financial system that is of the people and for the people. It is time we take our nation back and take our monetary system back from the big banks.

I recently introduced H.R. 2990, the National Emergency Employment Defense Act, to put the Federal Reserve under the Treasury, to end the practice of fractional reserve banking and to take control of our monetary policy and make sure it works for the people.

We can use our Constitutional authority to coin money and spend it into circulation to put millions of Americans back to work in a way that is noninflationary. The time for bold change is now.

The willingness of protesters to take on the Federal Reserve has even won encouragement from a Republican presidential contender, Congressman Ron Paul, who says: “If they were demonstrating peacefully, and making a point, and arguing our case, and drawing attention to the Fed—I would say, good!”

While other Republican candidates have been condemning the protests, President Obama remained characteristically silent.

White House press secretary Jay Carney would only say that: “to the extent that people are frustrated with the economic situation, we understand.”