Nutter v. Dougherty, et al. - Pennsylvania Supreme Court - December 28, 2007
http://www.aopc.org/OpPosting/Supreme/out/J-89-2007mo.pdf
State law pre-empts local lawmaking where
- a state statute specifically declares that it has "planted the flag of pre-emption in a field" (express pre-emption)
- a state statute "proclaimes a course of regulation and control which brooks no municipal intervention" (field pre-emption)
- local law contradicts or contravenes state law (conflict pre-emption)
