National security refers to the security of a nation state, including its citizens, economy, and institutions, and is regarded as a duty of government.
Originally conceived as protection against military attack, national security is now widely understood to include non-military dimensions, including the security from terrorism, crime, economic security, energy security, environmental security, food security, cyber security etc. Similarly, national security risks include, in addition to the actions of other nation states, action by violent non-state actors, narcotic cartels, and multinational corporations, and also the effects of natural disasters.
Governments rely on a range of measures, including political, economic, and military power, as well as diplomacy to enforce national security. They may also act to build the conditions of security regionally and internationally by reducing transnational causes of insecurity, such as climate change, economic inequality, political exclusion, and nuclear proliferation.