The ARRL serves as the primary representative of Amateur Radio operators to the US government. It performs this function by lobbying the US Congress and Federal Communications Commission or FCC.
ARRL is run by an elected board of directors who are responsible for setting League Policy. Each director serves a 2 year term and represents the members within their particular region of the US. There is also a field organization of volunteers which are supported by professional leagus staff.
The Field Organization of the ARRL is organized as "sections" with each section having a "Section Manager." The Section Manager is elected by the members living within his section for a two year term. The Section Manager has several different volunteers which serve as his local cabinet. The Section Emergency Coordinator, Official Observer Coordinator, Technical Coordinator, Section Traffic Coordinator are some of these cabinet members.
The Section Emergency Coordinator is responsible for the Amateur Radio Emergency Service, or ARES operation within the section. This is the largest single part of the field organization consisting of any volunteer who wishes to help with emergency and Public Service communications. (You don't need to be a league member to participate.)
The Technical Manager is responsible for assisting local amateurs with technical problems.
The Official Observer Coordinator runs the Amateur Auxiliary program within a section.
The Section Traffic Coordinator organizes the National Traffic System operations within the section.
The ARRL provides several services to it's members including the publishing of QST, the official journal of the ARRL, incoming and out-going QSL bureaus, publishing of technical and training books, and support of the field organization.