The tobacco industry is trying to head off a wave of state-based challenges regarding the light cigarettes, even as it is appealing a federal judge's order to stop marketing cigarettes as "low tar," "light," "ultra light" or "mild" because they mislead consumers.

The issue before the justices is whether state laws against unfair marketing practices may be used in suits against the tobacco companies or whether federal law bars such lawsuits. The Federal Cigarette Labeling and Advertising Act says states can't impose any requirements on the advertising or promotion of cigarettes.

A federal judge initially threw out a suit filed by three Maine residents against Altria Group Inc. and its Philip Morris USA Inc. subsidiary that alleged the advertising of light cigarettes was unfair and deceptive.

The 1st U.S. Circuit Court of Appeals in Boston, however, reinstated the suit.

The Maine plaintiffs said they smoked Marlboro Lights, made by Philip Morris, for at least 15 years. They claim the company marketed the cigarettes as "light" and having "lowered tar and nicotine" despite knowing that those statements were false, in violation of Maine's Unfair Trade Practices Act.

The company has research, the plaintiffs say, that shows it knew that smokers of the light cigarettes took deeper puffs and used other techniques to ensure they received as much nicotine as they would have gotten from regular cigarettes.

Philip Morris said the lawsuit was properly dismissed by the federal judge and called on the Supreme Court to resolve a conflict between appeals courts over these sorts of lawsuits. The 5th U.S. Circuit Court of Appeals in New Orleans last year dismissed a similar suit.

In the government's landmark case against tobacco companies, U.S. District Judge Gladys Kessler said the companies "distorted the truth about low tar and light cigarettes so as to discourage smokers from quitting."

That case is on appeal with the U.S. Circuit Court of Appeals for the District of Columbia.

A separate federal lawsuit filed by smokers is pending in New York. The class-action suit alleges tobacco companies violated federal racketeering laws by promoting light cigarettes as lower-risk alternatives to regular cigarettes even though their internal documents showed they knew the risks were about the same. The class may consist of as many as 60 million people, lawyers say.

The 2nd U.S. Circuit Court of Appeals in New York is considering whether the lawsuit can proceed as a class action or whether smokers must file suit individually.

The basics of the claims against the companies are similar in all the lawsuits: The companies knew that smokers may compensate for the lower tar and nicotine yields by taking deeper puffs, holding the smoke in their lungs longer or smoking more cigarettes.

The R.J. Reynolds Tobacco Company filed a brief in support of its chief rival, saying the financial stakes in the case are enormous.

The U.S. Chamber of Commerce, also backing Altria, said the appeals court ruling could extend well beyond cigarette labels to product liability lawsuits against many industries.