There were many contributors to the 2008-09 financial crisis, which led to the Great Recession and the still-slow economic recovery. Among the co-conspirators in the financial crisis were: Wall Street investment banks that pushed risky deals, mortgage lenders that relaxed loan standards, federal mortgage giants Fannie Mae and Freddie Mac that supported creation of more risky mortgages, home buyers who bought houses they could not afford. And don’t forget Congress, which pushed for higher levels of home ownership, without concern for the risks.

Among the lesser-known players creating conditions for the financial crisis were the rating agencies, three presumably independent companies that evaluated the risks of the packaged mortgage debt investment products, called collaterized debt obligations (CDOs), that were sold by Wall Street banks.

Last week, nearly five years after the depths of the financial crisis, federal prosecutors filed a civil lawsuit against Standard & Poor’s, the largest of the nation’s big rating agencies.

The Justice Department charges S&P with giving risky CDOs higher ratings than they deserved, based on the risks of the individual home mortgages packaged into the complex products sold to investors.

More than a dozen state prosecutors joined the case, saying that investors, including public pensions, were misled by inaccurate ratings from rating agencies.

Beyond the charge that S&P gave risky CDOs higher ratings than they deserved, federal prosecutors allege that S&P was influenced by Wall Street investment banks that were selling the CDOs to investors. The banks also paid fees to S&P, and it appears that conflict of interest led to favorable ratings that helped the banks sell the CDOs and make more profits.

The civil charges reportedly were filed after settlement talks broke down between S&P and the Justice Department. Federal officials had been pressing for a $1 billion settlement, which would wipe out one year’s profits for S&P’s parent, McGraw-Hill Companies.

Even if a conviction or a penalty exceeding the $1 billion that S&P rejected is not achieved, it’s important to have a public airing of the questionable practices surrounding the rating agencies’ involvement in the CDOs.

The conflict of interest seems clear, and testimony should reveal whatever pressure was applied by Wall Street to give the CDOs high-quality ratings. Big Wall Street banks made millions in profits selling the packaged mortgage investments.

The apparent failures of the rating agencies, including S&P, to flag the risks of the real estate bubble played a role in the financial crisis. But if the Justice Department can file a lawsuit against S&P, why not some big Wall Street investment banks? Why not the subprime lenders?

There is a list of people, organizations and government agencies seen as guilty when it comes to the financial crisis. But despite the public appetite to see top executives punished for the financial crisis, it’s woth remembering that greed and stupidity are not illegal. Experts say that winning such cases is difficult and Wall Street lawyers might outgun the government’s lawyers.

Winning the lawsuit against S&P might be a long shot. Even if it is, the public should be seeing similar long-shot lawsuits filed against high-level executives at Wall Street firms and subprime lenders. Those cases should compel public testimony from executives at Fannie Mae and even from members of Congress who pushed for more homeownership, regardless of the relaxed lending standards and risks.

The S&P lawsuit feels like a matter of too little, too late. But it’s still worth the effort.