On Monday, a single, ringing court decision gave hope that Wall Street will finally be held to account for its role in causing the financial crisis. Federal District Court Judge Jed Rakoff’s opinion may soon force the SEC, the federal government’s investment regulator, to take big banks to court, rather than continuing to come to terms with them in out-of-court settlements. Millions of Americans are no doubt looking forward to the prospect that deep-pocketed bankers will soon be receiving their comeuppance in open court.

But it’s an entirely open question whether the decision will amount to anything more than a symbolic victory. The court’s demand that the SEC be more aggressive failed to consider just how much the agency’s scope of action is already constrained by policymakers in the federal government. Rakoff wants regulators to redouble their efforts to investigate crimes committed by banks—but he may have inadvertently made the SEC’s job of recovering defrauded investors’ money that much harder.

THERE’S A GOOD REASON that the SEC has pursued out-of-court settlements. Successfully prosecuting white-collar crime is no easy matter, especially for the types of fraud prosecutors and financial reformers suspect were at the heart of the 2008 financial crisis. While federal prosecutors recently won a landmark insider trading case to put top executives behind bars, fraud can be harder to prove. In 2009, a jury acquitted two former Bear Stearns bankers the government charged with deceiving investors about the risks associated with CDOs, complex securities manufactured from packages of mortgage loans. The SEC, in fact, has yet to convict anyone in court on charges related to causing the financial crisis.

Instead, the agency’s main approach to accountability has been to leverage public opinion more than the law, using well-timed prosecutions to force major banks to pay penalties and change business practices in settlements. Of course, such settlements are flawed as instruments of justice. They rarely involve the acknowledgement of wrongdoing; individuals are rarely held accountable. And the sums of money are usually a pittance for the banks involved. In its 2010 landmark settlement, the SEC had Goldman Sachs agree to pay a $550 million penalty after it “misstated and omitted key facts”—a polite, and legally innocuous, way of saying it lied—about its CDOs. That same year Goldman made an $8.35 billion profit after paying its employees $15.4 billion.

Rakoff is not wrong to feel that these kinds of settlements are incommensurate with the injustices they’re addressing. The case he was asked to consider involved a $1 billion CDO sold by Citigroup to investors in 2007, just as the housing markets began to collapse: Not only did investors lose $847 million, but Citi, it turns out, bet against the security, gaining at least $160 million, and perhaps as much as $600 million, in profit. But even though the SEC had evidence strongly implicating the bank in fraud—including emails sent by staffers describing the CDO as “a collection of dogsh!t”—the announced settlement was only for a total of $285 million, and without any admission or denial of the allegation.