As Congress appears to have roused itself to action, so too has the Securities and Exchange Commission. Moody’s recently disclosed that the commission had warned that it might sue the company. At issue are a number of former Moody’s executives who allowed some European derivatives to keep their high ratings even after it became clear that the grades were the result of a computer glitch. The particulars of the suit, however, aren’t as important as the signal that it has sent.

“This along with the Goldman Sachs lawsuit is a clear indication that the S.E.C. wants us to believe that it’s getting tougher,” says Lawrence White, a professor of economics at New York University. “The S.E.C. wants the world to know that the cop is back on the beat.”

IT’S too early to say what Washington’s legislative and regulatory actions portend for the rating agencies, but already they have altered the sense, prevalent as recently as three months ago, that these companies are in a business so complicated, and operating in an economy so fragile, that it is best to leave them undisturbed.

Perhaps legislators have been emboldened to fiddle with our nation’s troubled financial machinery because the economy is stronger, making any tinkering less threatening to the entire contraption. Maybe it is part of a populist anger over Wall Street bonuses and the banks’ exceptionally strong earnings reports. Whatever the cause, the atmospherics have changed.

A similar shift might be happening in the courts, though if Ron Grassi’s lawsuit is any indication, beating the rating agencies legally is still a very difficult maneuver.

Image Mr. Grassi in the “war room” in his house. He sued the rating agencies after losing $40,000. Credit... Max Whittaker for The New York Times

The origins of his case can be traced to 2004, when he and his wife, Sally, were looking for very safe investments for their retirement years. A broker explained that the high ratings awarded by the three agencies — A+ from S.& P., A1 from Moody’s, AA-1 from Fitch — were proof the Lehman bonds were all but risk-free. They expected that by 2023, they would have their $40,000 in principal back, plus $90,000.