Not long ago, a group of skeptical Democratic senators met at the White House with President Obama, his chief economic adviser, Larry Summers, and Treasury Secretary Tim Geithner. The six senators—most of them centrists, joined by one left-leaning independent, Vermont's Bernie Sanders—said that while they supported Obama, they were worried. The financial reform policies the president was pursuing were not going far enough, they told him, and the people Obama was choosing as his regulators were not going to change things fundamentally enough. His appointed officials and nominees were products of the very system that brought us all this economic grief; they would tinker with the system but in the end leave Wall Street, and its practices, mostly intact, the senators suggested politely. In addition to Sanders, the senators at the meeting were Maria Cantwell, Byron Dorgan, Dianne Feinstein, Carl Levin and Jim Webb.

That March 23 gathering, the details of which have gone largely unreported until now, was just a minor flare-up in a larger battle for the future—one that may already be lost. With the financial markets seeming to stabilize in recent weeks, major Wall Street players are digging in against fundamental changes. And while it clearly wants to install serious supervision, the Obama administration—along with other key authorities like the New York Fed—appears willing to stand back while Wall Street resurrects much of the ultracomplex global trading system that helped lead to the worst financial collapse since the Depression.

At issue is whether trading in credit default swaps and other derivatives—and the giant, too-big-to-fail firms that traded them—will be allowed to dominate the financial landscape again once the crisis passes. As things look now, that is likely to happen. And the firms may soon be recapitalized and have a lot more sway in Washington—all of it courtesy of their supporters in the Obama administration. With its Public-Private Investment Program set to bid up and buy toxic assets, the administration is handing these companies another giant federal subsidy. But this time the money will come through the back door, bypassing Congress, mainly via FDIC loans. No one is quite sure how the program will work yet, but it's very likely going to make a lot of the same Wall Street houses much richer at taxpayer expense. Meanwhile, the big banks that still need help will almost certainly get another large infusion once the stress tests are completed by the end of the month.

The financial industry isn't leaving anything to chance, however. One sign of a newly assertive Wall Street emerged recently when a bevy of bailed-out firms, including Citigroup, JPMorgan and Goldman Sachs, formed a new lobby calling itself the Coalition for Business Finance Reform. Its goal: to stand against heavy regulation of "over-the-counter" derivatives, in other words customized contracts that are traded off an exchange. Companies like these kinds of contracts, which are agreed to privately between firms, because they allow them to tailor a hedge perfectly against a firm-specific risk for a  certain time period. But in order to preserve  its right to negotiate these cheaper private contracts, Wall Street is apparently willing to argue for the same lack of public transparency and  to permit the systemic risk that led to the crash.

Geithner's financial regulation plan, announced April 2, does address some of these concerns. The Treasury chief wants all standardized over-the-counter trading of derivatives to go through an industry clearinghouse, which will give the government more oversight. Geithner said he wants to require "systemically important" firms to reserve more capital. He also wants to rein in "customized" derivatives contracts—those agreed to privately between firms. Whereas once these trades went totally unregulated, Geithner would require that they be "reported to trade repositories and be subject to robust standards" for documenting and collateralizing, among other new rules.

But it's unlikely this will do much to change Wall Street. Geithner's new rules would allow the over-the-counter market to boom again, orchestrated by global giants that will continue to be "too big to fail" (they may have to be rescued again someday, in other words). And most of it will still occur largely out of sight of regulated exchanges. The response favored by the administration, the Federal Reserve and even many in Congress is to create a new all-knowing "systemic risk regulator" with as-yet-undetermined powers. Is such a person sitting at 30,000 feet really going to be able to keep up with all this onrushing complexity, especially as over-the-counter trading resumes in quiet places around the world? It is a triumph of hope over experience to think so.