The Supreme Court ruled Monday that Philip Morris Cos. Inc. cannot move a lawsuit by cigarette smokers into federal court.

The unanimous decision came in a case that consumers filed against the cigarette company in state court in Arkansas.

Philip Morris, a part of Altria Group Inc., moved the case to federal court in Little Rock, Ark., saying it could do so because the company was pervasively regulated by the Federal Trade Commission.

The court said the fact that a federal agency directs a company's activities does not permit removing the case to federal court.

The potential for large damage awards from state court juries makes the federal court system a more desirable place for tobacco companies and other defendants sued in class-action cases.

Consumers who smoked Marlboro Lights and Cambridge Lights alleged Philip Morris violated the Arkansas Deceptive Trade Practices Act. The company fraudulently marketed ''light'' cigarettes as having less tar and nicotine, the suit stated.

The company allegedly designed the cigarettes to register lower levels of tar and nicotine in government-approved testing than would be delivered to the consuming public.

At issue is an unusual use of a federal law on moving cases out of state courts. The law protects anyone acting under a federal officer from interference by hostile state courts.

''A highly regulated firm cannot find a statutory basis for removal'' to a federal court ''in the fact of regulation alone,'' wrote Justice Stephen Breyer. What the FTC is doing ''sounds to us like regulation, not delegation.''

Earlier versions of the law protected customs officers enforcing an unpopular embargo against England during the War of 1812, and protected federal revenue officers enforcing the nation's Prohibition laws in the 1920s.

(Published by The New York Times, June 11, 2007)