JPMorgan Chase Chairman and CEO Jamie Dimon at the Business Roundtable Headquarters in Washington on Dec. 3. Dimon has lobbied lawmakers for changes to the Dodd-Frank financial oversight regulations. (AP Photo/Jacquelyn Martin)

Wall Street’s biggest banks squeezed out a victory this week when the House narrowly approved a spending bill with provisions  that would weaken a section of the Dodd-Frank financial regulations. But the win came at a high cost for the banks -- in spending down their political capital and inflaming public opinion.

In fact, the apparent losers in the legislative debate – such as Rep. Maxine Waters (D-Calif.) and Sen. Elizabeth Warren (D-Mass.,) –  sounded like winners on Friday.

“I think we broke through,” Waters, the ranking member of the House Financial Services Committee, said in an interview Friday afternoon. Both legislators made fiery speeches before the vote, saying the change was a favor to powerful banking interests such as J.P. Morgan Chase and CitiGroup that put taxpayers at risk.

“Under the cover of ‘must pass’ legislation, big bank lobbyists are hoping that Congress will allow Wall Street to once again gamble with taxpayer money – by reversing a provision that prohibits banks from using taxpayer-insured funds, bank deposits, to engage in derivatives trading activity,” Waters said on the House floor. Derivative trades are basically a bet on the future value of things, such as commodities. For example, major airlines use derivatives to hedge against future price changes for jet fuel, as a way to keep ticket prices stable. Most of these transactions carry little risk.

But before the 2008 financial crisis, Wall Street firms used more complicated derivative formulas to place risky bets on the mortgage market. Their excesses nearly brought down the financial system. Dodd-Frank was intended to curb that behavior. Banks have pushed for exceptions to the regulations so they can once again use their deposits to underwrite some more complex derivative trades. Those deposits are often backed by federal insurance, which means taxpayers are on the hook for any risk.

The new language would effectively repeal portions of the “push-out” provision of Dodd-Frank, which requires banks to push some derivatives trading into separate units that do not have access to federal deposit insurance.

On Friday, Waters and her staff made plans to get together with allies on the left to discuss how to “better educate the public about what is at stake” in the debate over financial regulations, which will likely expand next year.

Among bank lobbyists, there was a similar discussion Friday. Several banking industry advocates interviewed by The Post said they expressed concern about the rapidly mobilized opposition to banking interests that developed on the left and the right this week.

In addition to labor and consumer groups sounding the alarm, some conservative opinion leaders also objected to the language added to the spending bill.

Some bankers objected that they were portrayed as being opposed to Dodd-Frank and other regulations -- and they called for new talking points for 2015.

“We are not advocating the repeal of Dodd Frank, but it is being portrayed that way,” said Francis Creighton, chief lobbyist for the Financial Services Roundtable, which has pushed for years for the change. “We want to make it clear that we (the industry) want Dodd Frank to work better so it will better serve our customers - and their constituents.” That message was embraced by lobbyists for other banks and trade associations.

On Friday, the chief of public affairs for Citi, Ed Skyler, wrote in a blog post that  “Citi has been and remains a strong supporter of financial reform, and specifically of Dodd-Frank. While most of Dodd-Frank was well considered and has strengthened our financial system,” a couple of sections including the one addressed in the House spending bill were problematic, Skyler wrote.

Going forward, bank lobbyists said they would present the argument for revisions in regulatory law as one that will help consumers and the economy, not necessarily the banks.

But opponents, such as Simon Johnson, former chief economist of the International Monetary Fund and a professor at the MIT Sloan School of Management, said changes in rules governing derivatives are all about profits for the big banks.

"There is a lot of money at stake," Johnson said.  Banking executives "want to be able to take big risks where they get the upside and the taxpayer gets the potential downside," he said.

The White House sought to deflect the torrent of criticism over the amendment to Dodd-Frank, reasserting that the administration was opposed to the change but willing to accept it as one of the compromises that went into the omnibus spending bill.

White House spokesman Josh Earnest noted that the Obama administration had earlier opposed an identical stand-alone measure that won veto-proof support in the House of Representatives, including 70 Democrats, 13 more than those who voted for the omnibus bill. “This is the essence of compromise,” Earnest said, adding that “on balance the president is pleased.”

“This is a difference over tactics not over principle,” Earnest said. “The president has opposed this provision for a number of years and opposes it now.”

A senior administration official said the change was not crippling to financial oversight. "We wouldn’t argue on the substance that this is a trivial or meaningless thing by any stretch of the imagination,” the official said, but added that it was not “one of the core foundational components” of Dodd-Frank.

He said that Dodd-Frank had made derivative trading more transparent and thus easier to regulate. He said that the omnibus bill’s sharp increase in funding for the Commodity Futures Trading Commission would give the regulator “a lot more juice” and make oversight more effective. Moreover, the senior administration official said, under the existing Dodd-Frank rules, about 90 percent of current derivative trades would be considered legitimate hedging and thus could remain on the books of insured banks.

The official said that other parts of Dodd-Frank also provided stronger capital requirements and other measures to reduce overall risk in the financial system.