The party of “no” said “no” again on Monday — this time to tightening regulation of the nation’s financial system.

While 57 Democratic and independent senators voted to open that long-delayed debate, Senate Republicans and a single Democrat (Nebraska’s Ben Nelson) blocked a cloture vote that would have opened the debate on repairing a financial system so vulnerable and dysfunctional that it has repeated brought the nation’s economy to the brink of collapse.

Monday’s 57-41 vote offered a powerful perspective regarding which side the Grand Old Party — which made its name a century ago as the champion of trust-busting legislation — is now on.

Tom McMahon of Americans United for Change summed things up when he said: “Look up ‘Quid pro quo’ in the dictionary and you’ll find a picture of Republican Senate Minority Leader Mitch McConnell with his hand out to hedge fund managers and banking executives just days before leading the filibuster against Wall Street reform. Pretending as if the financial crisis that cost over 8 million Americans their jobs never happened, Senate Republicans today stood in unanimous support of Wall Street over the Main Streets that suffered the consequences of the big banks’ greed and recklessness.”

McMahon’s assessment was blunt and unforgiving:

Senate Republicans stood in unanimous opposition to ending taxpayer bailouts, to shining a bright light on the shadowy derivatives markets, and establishing a new watchdog agency on Wall Street that will protect American consumers against Madoff-style scams. They did just what they were told by the 1,500 Wall Street lobbyists camped out their offices this week that got every dime’s worth of the $465 million they spent last year to kill reform.

Counting on Republicans to block financial reform was the safest and surest bet Wall Street executives have made in a very long time. But, with two-thirds of American people in support of stricter regulations for banks and other financial institutions, Senate Republicans just made the riskiest gamble of their careers. In the face of overwhelming public demand that Wall Street be held accountable for laying waste to our economy, it’s not a question of whether reform is going to pass — it’s a question of how long Republicans can run from the pitch forks on Main Street.

Some Democrats are already excited by the prospect of running fall races against Republicans who took the side of the big banks.

But one of the Senate’s most ardent reformers, Vermont Independent Bernie Sanders, was not thinking about the politics of the fall. He was worried about the reality of a banking system reforms that have been too long deferred.

“I am disappointed but not surprised that not a single Senate Republican voted to allow us to proceed to consideration of Wall Street reform,” said Sanders, who opposed the Wall Street bailout of 2008 and has been a steady critic of abuses by big banks and financial institutions.

Speaking of his Republican colleagues, Sanders said, “I hope they reconsider. To my mind, it is absolutely imperative that we end the greed, recklessness and illegal behavior on Wall Street which has led to the loss of millions of jobs and the worst recession in modern history.”

To help promote that reconsideration, thousands of Americans will gather on Wall Street Thursday to demand that the GOP do the right thing — and that the whole of the Senate (including reluctant Democrats) back real reform.

The AFL-CIO and National People’s Action have organized the afternoon protest so that “everyday people–small business owners and union members, homeowners and tenants, faith leaders, the employed and the unemployed–to join together in recognition of our shared fate and our commitment to democracy.”

On April 29th at 3:30pm, the groups say:

Thousands will converge on Wall Street to reclaim America with one simple message: Americans deserve an economy that works for all of us, not just Wall Street!

Wall Street and big banks like Bank of America and Wells Fargo crashed our economy leaving millions without housing, work, and critical services.

Join us as we take the fight for financial reform into the belly of the beast!

Wall Street insiders and their political allies may want to shut down the debate about financial reform.

But the people want a showdown, and they will have it Thursday.