Various priority services exist today in the public networks to support key personnel in their critical communications during a National Security and Emergency Preparedness (NS/EP) condition. These priority services will evolve as the public networks evolve to Next Generation Network (NGN) Internet Protocol (IP)-based infrastructures, including the 4G wireless network called Long Term Evolution (LTE). In addition to evolving the legacy priority Voice services to Voice over IP (VoIP), it is expected that NS/EP NGN Priority Services (NGN-PS) will include priority data and priority video services. NS/EP NGN-PS, and associated network capabilities, have been specified by the Office of Emergency Communications (OEC) and are based on industry Standards. During an NS/EP condition, the public networks can get overloaded due to heavy user traffic and possible failures. NS/EP NGN-PS provides the mechanisms in the access and core networks to facilitate the needed priority communications. In particular, the wireless access networks such as LTE may become severely overloaded in an area, affecting call admissions and Quality of Service (QoS). This paper describes the NS/EP priority mechanisms in LTE that address and mitigate the various potential LTE congestion points, to then facilitate the high probability of call and data admission and completion. These NS/EP priority mechanisms provide capabilities to access, invoke and maintain NS/EP NGN-PS, i.e., NS/EP voice, data and video priority services, for end-to-end user-to-user communications. These mechanisms will result in priority during (a) user attachment, (b) node signaling and processing, (c) device paging, (d) handover, (e) media bearer establishment, (f) radio resource admission, (g) packet transport, and (h) overload controls.