... of existing Federal laws/ regulatory requirements. The plaintiffs had sued in State court under 2 main theories: #1 That the company was in violation of State advertising laws; and, #2 That the company had lied and witheld information from the public.
The Supremes ruled that the tobacco companies couldn't be sued for deceit because they'd violated the State adevertising laws, but only under the Federal law which covered the subject of warning labels. That killed Argument #1.
At the same time, however, they said that the tobacco company could be sued for lying and misleading the public, because that wasn't a matter of the specific Federal warning-label law, but of the general American common-law obligation of companies not to decieve the public about health and safety matters....