The new White House approach has already prompted the Senate panel, led by Senator Christopher J. Dodd, Democrat of Connecticut, to interrupt those negotiations. On Tuesday, in the first of several hearings on Mr. Obama’s proposals, the committee will hear from Paul A. Volcker, a former Federal Reserve chairman, and the deputy Treasury secretary, Neal S. Wolin.
Republicans on the committee said Mr. Obama’s call for a bank tax was a political response to the unexpected loss of a Massachusetts Senate seat. And Democrats, although more positive about the president’s remarks, were slow to embrace the specifics, like the tax, of his proposals.
“There is no question that this was presented to stoke and jump in front of a lot of populist furor,” said Senator Bob Corker, a Tennessee Republican who is working with Senator Mark Warner, a Virginia Democrat, on the problem of securities firms being so big and interconnected that their collapse could bring down the financial system.
“I think everybody watching understands that this was a political undertaking and not necessarily a substance undertaking,” he said. “This is a soak-the-rich populist grab.”
Senator Judd Gregg, a New Hampshire Republican who is working with Senator Jack Reed, Democrat of Rhode Island, on regulation of derivatives and credit rating agencies, offered a similar assessment of the president’s intervention.
“I think it’s confused the issue considerably, because he’s basically fanned the fires of populism and in a lot of instances, populism doesn’t give you either good regulatory activity or strong markets,” Mr. Gregg said. “It undermines both, in many instances.”
Senator Jon Tester, Democrat of Montana, disagreed. “The president’s remarks — I don’t see them as threatening, I don’t see them as negative, I see them as more ideas added to the pot that we need to consider,” he said in an interview. “I don’t see them hampering this process one iota.”
But industry representatives and Democratic Congressional aides say the president’s new proposals have already provoked a sharp increase in the volume and energy of the lobbying on regulatory reform, with more chief executives stepping over their government relations staff to request personal meetings with lawmakers. The big banks, the lobbyists say, have become increasingly alarmed that the legislative process may move in unexpected directions outside their control.
Chief executives of big banks have been in Washington for meetings with White House and Treasury officials and lawmakers on Capitol Hill. Jamie Dimon, chief executive of JPMorgan Chase, had lunch with Mr. Obama last Tuesday, and then met separately on Friday with the Federal Reserve chairman, Ben S. Bernanke, and the Treasury secretary, Timothy F. Geithner.
And industry lobbyists and chief executives have been lining up outside the doors of senators.
“Those eight senators hold the keys,” said Scott E. Talbott, a lobbyist for Financial Service Roundtable, which represents big banks.
Beyond the Warner-Corker and Reed-Gregg pairings, Senators Charles E. Schumer, Democrat of New York, and Michael D. Crapo, Republican of Idaho, are leading negotiations on overhauling corporate governance and executive compensation.
The final pairing — Mr. Dodd and Senator Richard C. Shelby of Alabama, the senior Republican on the banking committee — is taking up the issue of whether to create a consumer financial protection agency to oversee credit cards, mortgages, debt collection and other financial activities.
The White House proposed such an agency last June, and a modified version was part of the House reform bill passed in December. Industry groups, like the American Bankers Association, have strongly opposed it.
“The further away we get from the near collapse of our financial system in the fall of 2008, the harder it is to convince members of Congress to take a tough vote,” said Travis B. Plunkett, legislative director for the Consumer Federation of America, which has made the consumer agency a centerpiece of its lobbying.
Neither Mr. Dodd nor Mr. Shelby would comment on the status of their talks.
Ever since his initial reform proposal met with a frosty reception in the banking committee last fall, Mr. Dodd has insisted that regulatory reform would require bipartisan support. The Massachusetts Senate outcome, which denies Democrats the 60-vote majority they need to overcome a Republican filibuster, has underscored that point.
Supporters of the president, however, said his intervention could help goad lawmakers to pass tough legislation, arguing that the widespread anger at Wall Street would make it awkward for legislators to stand in the way of a bill labeled reform.
At a meeting with Mr. Dodd last month, Mr. Obama endorsed the need for consumer protections. But he did not specifically mention the idea of a separate agency, and Senate Republicans have said they are against it.
Mr. Obama’s newest proposals — to ban banks with federally insured deposits from casting risky bets in the markets and to turn back the consolidation in the financial industry — have arguably made Mr. Dodd’s job harder.
Senator Warner said he hoped the negotiations would stay on track. “I think this is too important to allow to become a partisan fight, and I’m still hopeful that we will see a bipartisan solution,” he said. But when asked to offer a timetable, he chuckled, saying only, “Hopefully sooner, rather than later.”
Eric Dash contributed reporting from New York.