15 USC 1334 - Preemption

(a) Additional statements 
No statement relating to smoking and health, other than the statement required by section 1333 of this title, shall be required on any cigarette package.
(b) State regulations 
No requirement or prohibition based on smoking and health shall be imposed under State law with respect to the advertising or promotion of any cigarettes the packages of which are labeled in conformity with the provisions of this chapter.