The Supreme Court opened its new term Monday suggesting it would side with tobacco companies in their fight to block lawsuits over deceptive marketing of “light” cigarettes.

The court’s term begins, by law, on the first Monday in October. “The October 2008 term is now convened,” Chief Justice John Roberts told a packed courtroom that included retired Justice Sandra Day O’Connor.

The justices turned away hundreds of appeals that had accumulated over the summer before addressing the tobacco case.

Several justices were skeptical that state laws against fraudulent advertising could be used to sue the makers of “light” and “low-tar” cigarettes when a federal law on cigarette labeling rules out lawsuits that involve smoking and health.

“How do you tell it’s deceptive or not unless you look at smoking and health?,” asked Chief Justice John Roberts.

Three Maine residents sued Altria Group Inc. and its Philip Morris USA Inc. subsidiary under the state’s law against unfair marketing practices. The class-action claim represents all smokers of Marlboro Light or Cambridge Light cigarettes, both made by Philip Morris.

The lawsuit argues that the company knew for decades that smokers of light cigarettes compensate for the lower levels of tar and nicotine by taking longer puffs and compensating in other ways.

A federal district court threw out the lawsuit, but the 1st U.S. Circuit Court of Appeals said it could go forward.

The role of the Federal Trade Commission could be important in the outcome. The FTC is only now proposing to change rules that for years condoned the use of “light” and “low tar” in advertising the cigarettes, despite evidence that smokers were getting a product as dangerous as regular cigarettes.

The FTC “created this problem by tacitly approving the place of these figures in the advertisements,” Justice Samuel Alito said.

Douglas Hallward-Dreimeier, the Justice Department lawyer representing the FTC Monday, said the cigarette makers “should not be able to benefit from their own misleading of the commission.”

The tobacco industry faces dozens of similar lawsuits around the country.