A federal judge in New York today gave class-action status to a lawsuit that poses a major new threat to the tobacco industry by asserting that tobacco companies purposely misled consumers by marketing “light” cigarettes as a safer alternative to regular cigarettes. The ruling opens the door for millions, if not tens of millions, of Americans to join the lawsuit as plaintiffs. In his ruling, Judge Jack Weinstein of the Eastern District of New York, essentially said that any United States resident who has ever purchased a cigarette labeled “light” is part of the class represented in the suit. In...