The federal government is ... going after Wall Street's biggest credit rating firm for its role in pumping up the housing bubble. The Justice Department filed a lawsuit [on Feb. 4] against Standard & Poor's Corp. The suit accuses the company's analysts of issuing glowing reviews on troubled mortgage securities whose subsequent failure helped cause the worst financial crisis since the Great Depression. The action marks the first federal crackdown against a major credit rater, and it signals an untested legal tack after limited success in holding the nation's banks accountable for the part they played in the crisis. The government selected Los Angeles as the venue to file the lawsuit in part because it was one of the regions hardest hit when the bottom fell out of the housing market. Hundreds of thousands of California residents lost their homes to foreclosure, and others saw their wealth evaporate as properties plummeted in value. In addition to the Justice Department, several state attorneys general are investigating the ratings agency. States such as California and New York are expected to pursue their own investigations and legal action, people familiar with the matter said. The federal action does not involve any criminal allegations. Critics have complained that the government has yet to send any senior bankers or Wall Street executives to jail for potential illegal behavior that led to the crisis. But civil actions typically require a much lower burden of proof.