Recently, Washington State voted to make marijuana legal to possess and sell. However, the Washington Attorney General added that individual cities and counties within the state retain the right to ban pot within their borders.
Typically, state law dictates municipal law just as federal law dictates state law. Marijuana is illegal at the federal level, yet individual states like Colorado and Washington have voted on the issue and allowed its sale and possession. In the same way, although the state of Washington voted to legalize marijuana, individual cities and counties still reserve the right to ban the substance, and many have.
A recent article on the ABA Journal stated that, "Dozens of localities within the state restrict the use of marijuana, often by imposing a moratorium of up to one year on allowing marijuana businesses or, indirectly, by requiring businesses to comply with federal law."